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0.2-Percent-Annual-Chance Flood
The flood that has a 0.2-percent chance of being equaled or exceeded in any given year (also known as the 500-year flood).
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1-Percent-Annual-Chance Flood
The flood that has a 1-percent chance of being equaled or exceeded in any given year (also known as the 100-year flood).
10-Percent-Annual-Chance Flood
The flood that has a 10-percent chance of being equaled or exceeded in any given year (also known as the 10-year flood).
10-Year Flood
See 10-Percent-Annual-Chance Flood.
100-Year Flood
See 1-Percent-Annual-Chance Flood.
1st Draft Delta Plan
1st Staff Draft Delta Plan
Read public comments received on the 1st Staff Draft Delta Plan
1st Staff Draft Delta Plan
2 to 4 Family Residence
A residential building (excluding hotels and motels with normal room rentals for less than 6 months\ duration) containing no more than four dwelling units. Incidental occupancies such as office, professional, private school, or studio space are permitted if the total area of such occupancies is limited to less than 25 percent of the total floor area within the building.
2-Percent-Annual-Chance Flood
The flood that has a 2-percent chance of being equaled or exceeded in any given year (also known as the 50-year flood).
2nd Draft Delta Plan
2nd Staff Draft Delta Plan
Read public comments received on the 2nd Staff Draft Delta Plan
3rd Draft Delta Plan
3rd Staff Draft Delta Plan
Read public comments received on the 3rd Staff Draft Delta Plan
44 CFR Section 65.10 Requirements
See Section 65.10 Requirements.
4th Draft Delta Plan
4th Staff Draft Delta Plan
Read public comments received on the 4th Staff Draft Delta Plan
50-Year Flood
See 2-Percent-Annual-Chance Flood.
500-Year Flood
See 0.2-Percent-Annual-Chance Flood.
5th Draft Delta Plan
5th Staff Draft Delta Plan
Read public comments received on the 5th Staff Draft Delta Plan
6th Draft Delta Plan
7th Draft Delta Plan
Abandoned Wells
Wells that are abandoned but that have not been properly destroyed provide a vertical conduit for contamination of the aquifer. While there is no accurate count of the number of such abandoned wells in California, one estimate is that there are more than 1 million such wells that are potential vertical conduits for contamination of the aquifer. State law (Health and Safety Code § 115700) requires that such wells be destroyed. Some local jurisdictions require the old well to be destroyed before a permit is issued for construction of a new well. Context: Resource Management Strategy.
About Delta
Accredited Levee System
A levee system that FEMA has shown on a Flood Insurance Rate Map (FIRM) or Digital Flood Insurance Rate Map (DFIRM) as providing protection from the 1-percent-annual-chance or greater flood. This determination is based on the submittal of data and documentation as required by Section 65.10 of the NFIP regulations. The impacted area landward of an accredited levee system is shown as Zone X (shaded) on the FIRM or DFIRM except for areas of residual flooding, such as ponding areas, which are shown as Special Flood Hazard Area.
Acoustic Tags
Acre-Foot (af)
The volume of water that would cover one acre to a depth of one foot; equal to 43,560 cubic feet or 325,851 gallons.
The National Flood Insurance Act of 1968 and any amendments to it.
A structure, operating criteria, program, regulation, policy, or restoration activity that is intended to address a problem or resolve a conflict in the Bay-Delta system.
Actual Cash Value (ACV)
The cost to replace an insured item of property at the time of loss, less the value of physical depreciation.
Adaptation (Measures/Strategies)
Adjustments to natural and human systems to moderate harm or exploit beneficial opportunities in response to actual or expected effects of climate change.
Adaptive Capacity
The ability of systems, organizations, and individuals to (1) adjust to actual or potential adverse changes and events, (2) take advantage of existing and emerging opportunities that support essential functions or relationships, and/or (3) cope with adverse consequences, mitigate damages, and recover from system failures. It is an indicator of how well a system will adjust to and/or recover from external changes or large perturbations (e.g., severe floods or droughts). See also resilience.
Additional Document Form 399
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Additional Document Form 399 comments from Federal Agencies
Additional Document Form 399 comments from Individuals
Additional Document Form 399 comments from Local Agencies
Additional Document Form 399 comments from Other Organizations
Additional Document Form 399 comments from State Agencies
Additional Document Form 399 comments from Tribal Governments
Additional Reports
Adequate Progress Determination
A written determination issued by FEMA to the Chief Executive Officer of a community that has provided sufficient information for FEMA to determine that substantial completion of a flood protection system has been effected because: (1) 100 percent of the total financial project cost of the completed flood protection system has been authorized; (2) at least 60 percent of the total financial project cost of the completed flood protection system has been appropriated; (3) at least 50 percent of the total financial project cost of the completed flood protection system has been expended; (4) all critical features of the flood protection system, as identified by FEMA, are under construction, and each critical feature is 50 percent completed as measured by the actual expenditure of the estimated construction budget funds; and (5) The community has not been responsible for any delay in the completion of the system.
The act of judging or deciding by law. In the context of an adjudicated groundwater basin, landowners or other parties have turned to the courts to settle disputes over how much groundwater can be extracted by each party to the decision.
Abbreviation for acre feet; the volume of water that would cover one acre to a depth of one foot, or 325,851 gallons of water. On average, could supply l-2 households with water for a year. A flow of 1 cubic foot per second for a day is approximately 2 AF.
Anadromous Fish Restoration Program, part of the Central Valley Project Improvement Act. The AFRP identified instream and Delta flows needed for recovery of anadromous fish.
Ag Effective Precipitation on Irrigated Lands
Annual precipitation used by crops planted in developed irrigated land areas.
Agricultural Applied Water Use
The applied water use for irrigated agriculture including water applied for groundwater recharge.
Agricultural Discharge Standards
State and federal water quality regulations regarding discharge of water used foragricultural production to streams, rivers, groundwater aquifers, or evaporation ponds.
Agricultural Lands Stewardship
Conserving natural resources and protecting the environment by compensating owners of private farms and ranches for implementing stewardship practices.
Agricultural Water Use Efficiency
The ratio of applied water to the amount of water required to sustain agricultural productivity. Efficiency is increased through the application of less water to achieve the same beneficial productivity or by achieving more productivity while applying the same amount of water.
Agriculture Water Reliability (Average)
A measure of a water system’s ability to sustain the social, environmental, and economic agricultural systems that it serves during a year of average precipitation.
All Documents
Allocation of Long-Term Contractual Imports
Interregional allocation of water for periods of time more than one year through mechanisms such as the State and federal water projects.
Alluvial / Alluvium
A general term for clay, silt, sand, gravel, or similar unconsolidated detrital material, deposited during comparatively recent geologic time by a stream or other body of running water, as a sorted or semisorted sediment in the bed of the stream or on its floodplain or delta, as a cone or fan at the base of a mountain slope.
A collection of actions or action categories assembled to provide a comprehensive solution to problems in the Bay-Delta system.
Anadromous Fish
Fish that spend a part of their life cycle in the sea and return to freshwater streams to spawn.
Of human origin or resulting from human activity.
The formal objection to proposed and/or proposed modified Base Flood Elevations (BFEs) and/or base flood depths, submitted by a community official or an owner or lessee of real property within the community during the statutory 90-day appeal period. An appeal must be based on data that show the proposed or proposed modified BFEs or base flood depths are scientifically or technically incorrect.
Appeal Period
The statutory period, beginning on the date of second publication of proposed BFEs, proposed modified BFEs, proposed base flood depths, or proposed modified base flood depths in the local newspaper, during which community officials or owners or lessees of real property within the community may appeal the proposed or proposed modified BFEs and/or base flood depths by submitting data to show those BFEs or base flood depths are scientifically or technically incorrect.
Appeals Process
Appear on Delta Levee Investment Strategy page
This content will appear on the Delta Levee Investment Strategy Page
Application Forms
The comprehensive, easy-to-use forms that were implemented by FEMA in October 1992 to facilitate the processing of requests for revisions or amendments to NFIP maps.
Applied Water
The total amount of water that is diverted from any source to meet the demands of water users without adjusting for water that is used up, returned to the developed supply or irrecoverable. It is the quantity of water delivered to the intake to a city water system or factory or a farm headgate, directly or by incidental flows to a marsh or wetland for wildlife areas. For existing instream use, applied water demand is the portion of the streamflow dedicated to instream use or reserved under the federal or State Wild and Scenic Rivers acts or the flow needed to meet salinity standards in the Sacramento-San Joaquin Delta under State Water Board standards.
Applied Water (AW) Use
The total amount of water that is diverted from any source to meet the demands of water users without adjusting for water that is depleted, returned to the developed supply, or considered irrecoverable.
Applied Water Reduction
A decrease in the amount of water needed to meet the demand for beneficial use; can be a supply for both new (real) water and reused water. Context: Resource Management Strategy. See also new water.
Appropriative Right
The right to use water that is diverted or extracted by a nonriparian or nonoverlying party for nonriparian or nonoverlying beneficial uses. In California, surface water appropriative rights are subject to a statutory permitting process while groundwater appropriation is not. See also riparian rights and pueblo rights.
Approved Model
A numerical computer model that has been accepted by FEMA for use in performing new or revised hydrologic or hydraulic analyses for NFIP purposes. All accepted models must meet the requirements set forth in Subparagraph 65.6(a)(6) of the NFIP regulations.
Approximate Study
An engineering study that results in the delineation of floodplain boundaries for the 1-percent-annual-chance flood, but does not include the determination of BFEs or base flood depths.
April 2010
April 2011
April 2012
April 2013
April 2014
A body of rock or sediment that is sufficiently porous and permeable to store, transmit, and yield significant quantities of groundwater to wells and springs.
Aquifer Remediation
See groundwater remediation/aquifer remediation.
A confining bed or formation composed of rock or sediment that retards but does not prevent the flow of water to or from an adjacent aquifer. It does not readily yield water to wells or springs, but stores groundwater.
Area of Origin
Area of origin interests represent the water users and agencies located in the watershed where water supply originates. See also area of origin as defined in California Water Code Sections 11460 through 11463.
Artesian Aquifer
A body of rock or sediment containing groundwater that is under greater than hydrostatic pressure; that is, a confined aquifer. When an artesian aquifer is penetrated by a well, the water level will rise above the top of the aquifer. See also confined aquifer, semi-confined aquifer, and non-confined aquifer.
Artesian Pressure
Hydrostatic pressure of artesian water, often expressed in terms of pounds per square inch; or the height, in feet above the land surface, of a column of water that would be supported by the pressure.
Artificial Recharge
The (intentional) addition of water to a groundwater reservoir by human activity, such as putting surface water into dug or constructed spreading basins or injecting water through wells. Also referred to as intentional recharge or managed recharge. See also Category 1 recharge areas.
A term used to describe mapping and mapping-related data that reflect conditions within a floodplain based on flood-control and other structures being completed.
August 2010
August 2011
August 2012
August 2013
August 2014
Available Groundwater Storage Capacity
The volume of a groundwater basin that is unsaturated and capable of storing groundwater.
Available Soil Water
The amount of water held in the soil that can be extracted by a crop; often expressed in inches per foot of soil depth. It is the amount of water released between in situ field capacity and the permanent wilting point.
Average Annual Cost of Implementing Option
Annualized total monetary cost of option required for “turnkey” implementation including environmental and third party impact mitigation, storage, conveyance, energy, capitalized operations and maintenance, administrative, planning, legal and engineering costs.
Average Annual Runoff
The average value of total annual runoff volume calculated for a selected period of record, at a specified location, such as a dam or stream gage. (cf. normal)
Average Year Water Demand
Demand for water under average hydrologic conditions for a specific level of development.
B(2) Water
Statutory mandate to manage the water dedicated to fish and wildlife purposes pursuant to Section 3406(b)(2) of the Central Valley Project Improvement Act.
Background Materials
Background Water Conservation
The amount of conservation occurring independent of the best management practices and efficient water management practices (e.g., plumbing code changes, natural placement, actions water users implement on their own).
Banks Pumping Plant
The State Water Project (SWP) export pumping plant in the south Delta. The plant is located downstream of Clifton Court Forebay.
Base Flood
The flood having a 1% chance of being equaled or exceeded in any given year.
Base Flood Elevation (BFE)
The elevation shown on the Flood Insurance Rate Map (FIRM) for Zones AE, AH, A1-A30, AR, AR/A, AR/AE, AR/A1-A30, AR/AH, AR/AO, V1-V30, and VE that indicates the water surface elevation resulting from a flood that has a 1% chance of equaling or exceeding that level in any given year.
Any area of the building, including any sunken room or sunken portion of a room, having its floor below ground level (subgrade) on all sides.
See Hydrologic Basin
Basin Irrigation
Irrigation by flooding areas of level land surrounded by dikes. Used interchangeably with level border irrigation, but usually refers to smaller areas. Basin management objectives (BMOs) – See management objectives.
Basin Plan
A Basin Plan establishes a comprehensive program of actions designed to preserve, enhance, and restore water quality in all water bodies within California. The Basin Plan is each Regional Water Board’s master water quality control planning document. It designates beneficial uses of surface water and groundwater and water quality objectives that protect those uses.
The Bay-Delta Advisory Council, a 34-member federally chartered citizens’ advisory committee. BDAC provides formal comment and advice to the CALFED agencies during regularly scheduled meetings.
Beneficial Use
(1) As part of the nine Regional Water Quality Control Board’s Basin Planning efforts, up to 25 water quality beneficial use categories for water have been identified for mostly human and instream uses. From Section 13050(f) of California\s Porter-Cologne Water Quality Control Act: ‘Beneficial uses’ of the waters of the state that may be protected against water quality degradation include, but are not necessarily limited to, domestic, municipal, agricultural, and industrial supply; power generation; recreation; aesthetic enjoyment; navigation; and preservation and enhancement of fish, wildlife, and other aquatic resources or preserves. (2) As stated in Section 1240 of the California Water Code: An appropriation must be for some useful or beneficial purpose, and when the appropriator or successor in interest ceases to use it for such a purpose (typically five years or greater) the right ceases. In this context, beneficial uses are defined in the California Code of Regulations. Categories of beneficial uses recognized in California include the following: Aquaculture, raising fish or other aquatic organisms not for release to other waters; Domestic, water used by homes, resorts, or campgrounds, including water for household animals, lawns, and shrubs; Fire Protection, water to extinguish fires; Fish and Wildlife, enhancement of fish and wildlife resources, including raising fish or other organisms for scientific study or release to other waters of the state; Frost Protection, sprinkling to protect crops from frost damage; Heat Control, sprinkling to protect crops from heat; Industrial Use, water needs of commerce, trade, or industry; Irrigation, agricultural water needs; Mining. Hydraulicking, drilling, and concentrator table use; Municipal, city and town water supplies; Power, generating hydroelectric and hydromechanical power; Recreation, boating, swimming, and fishing; Stock watering, commercial livestock water needs; Water Quality Control, protecting and improving waters that are put to beneficial use.
Horizontal strips or shelves of material built contiguous to the base of either side of levee embankments for the purpose of providing protection from underseepage and erosion, thereby increasing the stability of the embankment or reducing seepage.
Best Available Science
Best Management Practices (BMP)
An urban water conservation measure that the California Urban Water Conservation Council agrees to implement among member agencies. The term is also used in reference to water quality standards, watershed management activities, and others.
A relatively large area of land or water, that characterize a geographically distinct assemblage of natural communities and species.
Blending Treatment
A process of reducing the concentration of a contaminant in one water source by blending or dilution with water that has a lower concentration.
Blue Water
The remaining fraction of water that is not consumed by evapotranspiration. See also green water.
Border Irrigation
Irrigation by flooding strips of land, rectangular in shape and cross leveled, bordered by dikes. Water is applied at a rate sufficient to move it down the strip in a uniform sheet. Border strips having no downfield slope are referred to as level border systems. Border systems constructed on terraced lands are commonly referred to as benched borders.
Brackish Water
Water with a salinity that exceeds normally acceptable standards for municipal, domestic, and irrigation uses, but less than that of seawater.
See Levee Breach.
Breakaway Wall
A wall that is not part of the structural support of the building and is intended through its design and construction to collapse under specific lateral loading forces, without causing damage to the elevated portion of the building or supporting foundation system.
Brown Bag
Brownfield Land
Underutilized real estate assets or land. Context: Resource Management Strategy Bulletin No. 118 DWR’s report California’s Groundwater Bulletin 118; updated in 2003.
See Structure.
Groundwater models covering the Central Valley, which has a three groundwater layers.
California Native American Tribe
A federally recognized California Native American Tribe or a non-federally recognized California Native American tribe that is on the contact list maintained by the Native American Heritage Commission.
CALSIM (California Water Resources Simulation Model)
A DWR-developed surface water storage allocation model for the State Water Project. CALSIM II is the latest application of the generic CALSIM model to simulate State Water Project/Central Valley Project operations. The model is a product of joint development between the California Department of Water Resources and US Bureau of Reclamation.
Capacity Building
Capacity building is the process of equipping entities, usually public agencies, with certain skills or competences, or for general upgrading of its performance capability by providing assistance, funding, resources, training, etc. Three fundamental elements of conjunctive management: project construction, groundwater management, and capacity building.
Carriage Water
Additional flows released during export periods to ensure maintenance of water quality standards and assist with maintaining natural outflow patterns in Delta channels. For instance, a portion of transfer water released from upstream of the Delta intended for export from south Delta would be used for Delta outflow.
Catastrophic Vulnerability
The probability and magnitude of potential negative economic, public health, and environmental impacts associated with water management actions. Context: Scenario Factor, Evaluation Criteria.
The area of land which catches and collects water above a reservoir or other storage structure.
Category 1 Recharge Area
Areas that are active recharge areas at the present time under the control of water management agencies. The infiltration rate at these areas is high, and they are carefully managed to maintain that high infiltration rate and to protect the quality of the water that is being recharged. At most sites monitoring activities track groundwater levels, rate of movement of the recharged water into the aquifer, and chemical changes. (cf. Category 2 and Category 3 recharge areas)
Category 2 Recharge Area
Areas that are known to have a fairly high infiltration rate, but that are not under the control of a water management agency. There may be little or no monitoring. (cf. Category 1 and Category 3 recharge areas)
Category 3 Recharge Area
Areas with a lower infiltration rate that makes the area much less suitable for an artificial recharge program managed by a local water agency. These areas may be subject to a lower degree of monitoring and management of potential contaminating activities. (cf. Category 1 and Category 2 recharge areas)
Central Valley Project (CVP) Deliveries
(1) The volume of water imported to a given area through the Central Valley Project. (2) CVP-Base Deliveries: The delivery of prior rights water to CVP contractors; CVP Project Deliveries: The delivery of project water to CVP contractors.
Central Valley Project Improvement Act (CVP)
<p>This federal legislation, signed into law on October 30, 1992, mandates major changes in the management of the federal Central Valley Project. The CVPIA puts fish and wildlife on an equal footing with agricultural, municipal, industrial, and hydropower users.</p> <p><a href="#top">Back to top</a></p>
Central Valley Salinity Alternatives for Long Term Sustainability
CV-SALTS is a regional collaborative salinity management effort.
CEQA Process
CEQA Process Meetings
Certification of Consistency
A naturally or artificially created open conduit that periodically or continuously contains moving water or which forms a connecting link between two bodies of water.
Channel Capacity
The maximum flow that can pass through a channel without overflowing the banks.
Channel Islands
Natural, unleveed land masses within Delta channels. Typically good sources of habitat.
Check Irrigation
Modification of a border strip with small earth ridges or restrictions (checks) constructed or inserted at intervals to retain water as it flows down the strip.
Chico CA
Chief Executive Officer (CEO)
The official of a community who has the authority to implement and administer laws, ordinances, and regulations for that community.
See California Irrigation Management Information System
Clarksburg CA
Clifton Court Forebay
The in-Delta storage used to regulate flows to the Banks Pumping Plant.
Climate Change
Climate Change
Changes in average annual temperature and precipitation and their monthly patterns in 2050 compared to today.
Closed Basin
No stream naturally exits the basin.
Closure Devices
Any movable and essentially watertight barriers, used during flood periods to close openings in levee systems, securing but not increasing the levee systems’ design level of protection.
Cloud Seeding
See precipitation enhancement
Coastal Flooding
Flooding that occurs along the Great Lakes, the Atlantic and Pacific Oceans, and the Gulf of Mexico.
Coastal High Hazard Area
An area of special flood hazard extending from offshore to the inland limit of a primary frontal dune along an open coast and any other area subject to high-velocity wave actions from storms or seismic sources.
Code of Federal Regulations (CFR)
The codification of the general and permanent rules published in the FEDERAL REGISTER by the Executive Departments and agencies of the Federal Government. NFIP regulations are printed in Parts 59 through 77 of Title 44 of the CFR.
Colorado River Deliveries
(1) The volume of water diverted from the Colorado River by Metropolitan Water District of Southern California, Imperial Irrigation District, Coachella Valley Water District, the Yuma Project, and others under California’s entitlement to use Colorado River water. (2) California has the right to import from the Colorado River. California’s allocation is 4.4 million acre-feet per year plus 50% of any declared surplus.
Commercial Activity Mix
The mix of high- and low-water using commercial activity. Note that commercial activity is broken into two factors: total commercial activity and commercial activity mix. The latter factor allows designation of the type of commercial activity that is occurring. See also total commercial activity.
Common Delta Pool
Delta provides a common resource, including fresh water supply for all Delta water users, and all those whose actions have an impact on the Delta environment share in the obligation to restore, maintain and protect Delta resources, including water supplies, water quality, and natural habitat.
Community (1)
A political entity that has the authority to adopt and enforce floodplain ordinances for the area under its jurisdiction. In most cases, a community is an incorporated city, town, township, borough, village, or an unincorporated area of a county or parish. However, some states have statutory authorities that vary from this description.
Community (2)
Any State or area or political subdivision thereof, or any Indian tribe or authorized tribal organization, or Alaska Native village or authorized native organization, which has the authority to adopt and enforce floodplain management regulations for the areas within its jurisdiction.
Community Assistance Call (CAC)
A telephone call made by FEMA Regional Office staff or the State NFIP Coordinator to a community to supplement or replace a Community Assistance Visit.
Community Assistance Program (CAP)
A FEMA program, funded by the NFIP, under which cost-shared funds are provided to States to provide technical assistance support to communities participating in the NFIP. The purpose of the CAP is to identify, prevent, and resolve floodplain management issues in NFIP participating communities before a flood occurs, or before poor performance or noncompliance warrant enforcement and intervention by FEMA.
Community Assistance Program-State Support Services Element (CAP-SSSE)
A FEMA program through which FEMA provides funding to States to provide technical assistance to communities in the NFIP and to evaluate community performance in implementing NFIP floodplain management activities.
Community Assistance Visit (CAV)
A visit by FEMA Regional Office staff or the State NFIP Coordinator to a community to assess whether the community’s floodplain management program meets NFIP participation requirements.
Community Coordination Meeting
A meeting during which FEMA Regional Office staff, State NFIP Coordinators, community officials, and other project team members or stakeholders discuss scope and plans for a study/mapping project, interim results of a study/mapping project, and final results of a study/mapping project for a particular community or group of communities.
Community Rating System (CRS) (1)
A FEMA initiative, established under the National Flood Insurance Program, to recognize and reward communities that have implemented floodplain management measures beyond the minimum required by NFIP regulations. Under the CRS, those communities that choose to participate voluntarily may reduce the flood insurance premium rates for property owners in the community by taking these additional actions.
Community Rating System (CRS) (2)
A program developed by the FEMA Mitigation Division to provide incentives for those communities in the National Flood Insurance Program that have gone beyond the minimum floodplain management requirements to develop extra measures to provide protection from flooding.
Community Water System
A public water system that serves at least 15 service connections used by yearlong residents or regularly serves at least 25 yearlong residents. See also public water system.
Compliance Period
The period that begins with the issuance of a Letter of Final Determination and ends when a new or revised FIRM or DFIRM becomes effective. During the compliance period, a community must enact and adopt new or revised floodplain management ordinances required for participation in the NFIP.
Conceptual Model
An explicit description of the critical cause-and-effect pathways in ecosystem function. A conceptual model includes a summary of current knowledge and hypotheses about ecosystem structure and function, and highlights key uncertainties where research might be necessary. Alternative or competing conceptual models illustrate areas of uncertainty, paving the way for suitably-scaled experimental manipulations designed both to restore and explore the ecosystem. Conceptual models also help to define monitoring needs, and bases for quantitative modeling.
Concord CA
That form of ownership of real property in which each unit owner has an undivided interest in common elements.
Confined Aquifer
An aquifer that is bounded above and below by formations of distinctly lower permeability than that of the aquifer itself. An aquifer containing confined groundwater. See also artesian aquifer. (cf. unconfined aquifer, semi-confined aquifer)
Conjunctive Management (Use) of Surface and Groundwater Storage
Coordinated and planned management of both surface and groundwater resources in order to maximize the efficient use of the resource; that is, the planned and managed operation of a groundwater basin and a surface water storage system combined through a coordinated conveyance infrastructure. Water is stored in the groundwater basin for later and planned use by intentionally recharging the basin during years of above-average surface water supply. Surface water and groundwater resources typically differ significantly in their availability, quality, management needs, and development and use costs. Managing both resources together, rather than in isolation from one-another, allows water managers to use the advantages of both resources for maximum benefit. Context: Resource Management Strategy
Conservation Offset
Actions by developer of a proposed project to save water at or above the demand level of the project.
Conservation Tillage
A tillage practice that leaves plant residues on the soil surface for erosion control and moisture conservation.
Consultation Coordination Officer (CCO)
The individual on the FEMA Regional Office staff who is responsible for coordinating with a community on activities related to the NFIP.
Consumed Fraction
The portion of agricultural applied irrigation water that satisfies evapotranspiration.
Consumptive Use
A quantity of applied water that is not available for immediate or economical reuse. It includes water that evaporates, transpires, or is incorporated into products, plant tissue, or animal tissue. Consumptively used water is removed from available supplies without return to a water resource system (uses such as manufacturing, agriculture, landscaping, food preparation, and in the case of Colorado River water, water that is not returned to the river.) cf. nonconsumptive use
Any substance or property preventing the use or reducing the usability of the water for ordinary purposes such as drinking, preparing food, bathing washing, recreation, and cooling. Any solute or cause of change in physical properties that renders water unfit for a given use. (Generally considered synonymous with pollutant.)
Contaminant Plume
A mixture of chemicals or leachate in groundwater at a certain concentration or toxicity.
A pipeline, canal, natural channel or other similar facility that transports water from one location to another.
Conveyance Evaporation and Evapotranspiration-Ag
The irrecoverable water from major water supply conveyance systems due to evaporation and evapotranspiration by vegetation in and near canals attributed to water delivered to agricultural uses; - Managed Wetlands – The irrecoverable water from major water supply conveyance systems due to evaporation and evapotranspiration by vegetation in and near canals attributed to water delivered to managed wetlands uses; - Urban – The irrecoverable water from major water supply conveyance systems due to evaporation and evapotranspiration by vegetation in and near canals attributed to water delivered to urban uses.
Conveyance Facilities
Canals, pipelines, pump lifts, ditches, etc. used to move water from one area to another.
Conveyance Irrecoverable Water
The amount of water that evaporates is used by plants (evapotranspiration) and percolates to a salt sink during transport.
Conveyance Outflow
The outflow needed to meet water quality and beneficial uses in the Delta. See also outflow. Conveyance Outflow to Mexico – The estimated annual flow of water from the All American Canal to seepage flowing to Mexico.
Conveyance Return Flows to Developed Supply (other HR)-Ag
The portion of agricultural conveyance water that seeps through channels and returns as surface flow in another hydrologic region. Data shown in Portfolio by Planning Area table (Volume 5 Technical Guide) include Conveyance Return Flows to Developed Supply for both PA and region. - Urban – The portion of urban conveyance water that seeps through channels and returns as surface flow in another hydrologic region. Data shown in Portfolio by Planning Area table (Volume 5 Technical Guide) include Conveyance Return Flows to Developed Supply for both Planning Areas and region. - Managed Wetlands – The portion of managed wetlands conveyance water that seeps through channels and returns as surface flow in another hydrologic region. Data shown in Water Portfolio by Planning Area table (Volume 5 Technical Guide) include Conveyance Return Flows to Developed Supply for both Planning Area and Region.
Conveyance Seepage-Ag
The portion of agricultural conveyance water that seeps through channels and returns to surface or groundwater. - Managed Wetlands – The portion of managed wetlands conveyance water that seeps through channels and returns to surface or groundwater. - Urban – The portion of urban conveyance water that seeps through channels and returns to surface or groundwater.
Cooperating Technical Partners (CTP) Program
An innovative FEMA program to create partnerships between FEMA and participating NFIP communities, regional agencies, and State agencies that have the interest and capability to become more active participants in Flood Map Modernization.
Cost of Reliability Enhancement
The total cost required to add an increment of reliability.
Cost of Unreliability
The sum of the forgone long-term value and short-term costs incurred to the users.
Cost Recovery
Designates who (marginal or existing users) pays the marginal and existing water costs. Also specifies circumstances where other revenue sources are used to recover costs. Costs can include capital, operation and maintenance, financing, environmental compliance (documentation, permitting and mitigation), etc.
Council Meetings
Countywide Format
A format used by FEMA to show flooding information for the entire geographic area of a county, including the incorporated communities in the county, on one map and in one report.
Cover Crop
Close growing crop that provides soil protection, seeding protection, and soil improvement between periods of normal crop production, or between trees in orchards and vines in vineyards. When plowed under and incorporated into the soil, cover crops may be referred to as green manure crops.
Cover Letter
Covered Action Determination
Covered Actions
See Levee Crevasse.
Critical Conditions of Overdraft
A groundwater basin in which continuation of present practices would probably result in significant adverse overdraft-related environmental, social, or economic impacts. The definition was created after an extensive public input process during the development of the Bulletin 118-80 report.
Critical Features
Integral and readily identifiable parts of a levee or other flood protection system, without which the flood protection provided by the entire system would be compromised.
Crop Coefficient
A numerical factor (normally identified as Kp or Kc) that relates the evapotranspiration (ET) of the individual crop (ETc) to reference evaporation or some other index.
Crop Idling
The temporary or permanent fallowing of land previously under irrigation that results in a reduction in stresses to a water system (e.g., alternate land use must result in a reduction in water use and/or enhancement of water quality).
Crop Rotation
A system of farming in which successions of different crops are planted on the same land area, as opposed to growing the same crop time after time (monoculture).
Crop Unit Water Use
The volume of irrigation water used per unit area of land, commonly expressed in acre feet per acre. As used in scenario evaluation, a change in unit water use can be a function of evapotranspiration rates and cultural practices, but NOT use efficiency. Agricultural use efficiency is captured under its own distinct factor.
Cultural Features
Railroads, airfields, streets, roads, highways, levees, dikes, seawalls, dams and other flood-control structures, and other prominent manmade features and landmarks shown on an NFIP map.
De-Accredited Levee System
A levee system that was once shown on the FIRM or DFIRM as providing protection from the 1-percent-annual-chance or greater flood, but is no longer accredited with providing this protection because FEMA has not been provided with sufficient data and documentation to determine that the levee system continues to meet the NFIP regulatory requirements cited at 44 CFR Section 65.10. The impacted area landward of a de-accredited levee system is shown on a new DFIRM as a Special Flood Hazard Area, labeled Zone A or Zone AE, depending on the type of engineering study that was performed for the area.
December 2010
December 2011
December 2012
December 2014
Dedicated (or Developed) Water Supplies
Water distributed among urban and agricultural uses, used for protecting and restoring the environment, or storage in surface water and groundwater reservoirs. In any year, some of the dedicated supply includes water that is used multiple times (reuse) and water held in storage from previous years. This is about 40 to 50 percent of the total annual water supply received from precipitation and imported from Colorado, Oregon, and Mexico.
Deep Percolation
(1) Movement of applied water to usable groundwater aquifer. Water that is applied for agricultural, urban, and managed wetlands in excess of the net use requirements. Water either is applied for groundwater recharge or percolates naturally to the water table. This does not include reuse, evaporation, evapotranspiration of applied water, or flows/percolation to a salt sink. (2) Percolation of water through the ground and beyond the lower limit of the root zone of plants into groundwater. Efficient agricultural and urban irrigation practices limit or eliminate deep percolation.
Deep Percolation Depletion
<p>Movement of applied water to usable groundwater aquifer. The quantity of water consumed, discharged to salt sink within a service area, or moved outside the service area and no longer available as a source of supply within the service area.</p> <p><a href="#top">Back to top</a></p>
Delta Council Meeting
Delta Council Meetings
Delta Discussions
Delta Inflow
The combined water flow entering the Delta at a given time from the Sacramento River, San Joaquin River, and other tributaries.
Delta ISB
Delta Islands
Islands in the Sacramento-San Joaquin Delta protected by levees. Delta Islands provide space for numerous functions including agriculture, communities, and important infrastructure such astransmission lines, pipelines, and roadways.
Delta Levee Investment Strategy
Delta Outflow
The net amount of water (not including tidal flows) at a given time flowing out of the Delta towards the San Francisco Bay. The Delta outflow equals Delta inflow minus the water used within the Delta and the exports from the Delta.
Delta Plan
Delta Plan
Delta Plan
Delta Plan
Delta Plan - Second Draft
Delta Plan Draft Programmatic EIR
Delta Plan Final
Delta Plan Final Redline
Delta Plan Implementation Committee
Delta Plan Scoping
Delta Plan Scoping and NOP
Read public comments received on the Scoping meetings and NOP
Delta Primary Zone
This zone is the Sacramento-San Joaquin River Delta land and water area of primary State concern and statewide significance as described in Section 12220 of the Water Code, but not within either the urban limit line or sphere of influence line of any local government\s general plan or studies existing as of January 1, 1992. The precise boundary lines of the Primary Zone includes the land and water areas as shown on the map titled "Delta Protection Zones" on file with the California State Lands Commission. Where the boundary between the Primary Zone and Secondary Zone is a river, stream, channel, or waterway, the boundary line shall be the middle of that river, stream, channel, or waterway. The Primary Zone consists of approximately 500,000 acres. Cal. Pub. Resources Code Section 29728.
Delta Science Plan
Delta Science Program
Delta Secondary Zone
This zone is the Sacramento-San Joaquin River Delta land and water area within the boundaries of the legal Delta not included within the Primary Zone, subject to the land use authority of local government, and that includes the land and water areas as shown on the map referenced in Delta Primary Zone above. The Secondary Zone consists of approximately 238,000 acres. Cal. Pub. Resources Code Section 29731
Delta Smelt
Delta Stewardship Council Public Hearing Transcripts
Delta Stressors Workshop
Demand Management
Programs that seek to reduce demand for water through conservation, rate incentives, drought rationing, and other activities.
The quantity of water consumed, discharged to salt sink within a service area, or moved outside the service area and no longer available as a source of supply within the service area.
Water treatment process for the removal of salt from water for beneficial use. Source water can be brackish (low salinity) or seawater. See total desalination.
Detailed Analysis Units
DAUs are the smallest study area for the analysis of water supply and use.
Detailed Study
An engineering study that, at a minimum, results in the delineation of floodplain boundaries for the 1-percent-annual-chance flood and the determination of BFEs and/or base flood depths.
Detention Ponds
A basin that stores storm water flows for a limited amount of time thereby reducing the amount of flow downstream of the basin.
Developed Area
An area of a community that is: (a) A primarily urbanized, built-up area that is a minimum of 20 contiguous acres, has basic urban infrastructure, including roads, utilities, communications, and public facilities, to sustain industrial, residential, and commercial activities, and (1) within which 75 percent or more of the parcels, tracts, or lots contain commercial, industrial, or residential structures or uses; or (2) Is a single parcel, tract, or lot in which 75 percent of the area contains existing commercial or industrial structures or uses; or (3) Is a subdivision developed at a density of at least two residential structures per acre within which 75 percent or more of the lots contain existing residential structures at the time the designation is adopted. (b) Undeveloped parcels, tracts, or lots, the combination of which is less than 20 acres and contiguous on at least 3 sides to areas meeting the criteria of paragraph (a) at the time the designation is adopted. (c) A subdivision that is a minimum of 20 contiguous acres that has obtained all necessary government approvals, provided that the actual ``start of construction\\ of structures has occurred on at least 10 percent of the lots or remaining lots of a subdivision or 10 percent of the maximum building coverage or remaining building coverage allowed for a single lot subdivision at the time the designation is adopted and construction of structures is underway. Residential subdivisions must meet the density criteria in (a)(3) above.
Developed Water Supply
See Dedicated Water Supplies
Any manmade change to improved or unimproved real estate, including but not limited to buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations or storage of equipment or materials.
Dewvaporation (Atmospheric Pressure Desalination)
Desalination through humidification and subsequent dehumidification (collection of evaporated water).
Diamond Bar CA
Digital Elevation Model (DEM)
A file with terrain elevations recorded for the intersection of a fine-grained grid and organized by quadrangle as the digital equivalent of the elevation data on a topographic base map.
Digital Flood Insurance Rate Map (DFIRM)
A FIRM that has been prepared as a digital product, which may involve converting an existing manually produced FIRM to digital format, or creating a product from new digital data sources using a Geographic Information System environment. The DFIRM product allows for the creation of interactive, multi-hazard digital maps. Links are built into an associated database to allow users options to access the engineering backup material used to develop the DFIRM, such as hydrologic and hydraulic models; Flood Profiles; data tables; DEMs; and structure-specific data, such as digital elevation certificates and digital photographs of bridges and culverts.
Digital Flood Insurance Rate Map (DFIRM) Spatial Database
A database designed to facilitate collecting, storing, processing, and accessing data developed by FEMA, enabling Mapping Partners to share the data necessary for the DFIRM production and conversion process. Where possible, all mapping and engineering data elements are linked to physical geographic features and georeferenced. The use of a Geographic Information System as a component of the DFIRM spatial database provides the ability to georeference and overlay the mapping and engineering data, allowing the database to support a wide variety of existing and forthcoming FEMA engineering and mapping products.
Digital Orthophoto Quadrangle (DOQ)
Photographic maps distributed by the U.S. Geological Survey. A DOQ is an aerial photograph that is adjusted to remove distortions caused by variations in terrain and the camera lens to produce a photograph that displays features in their planimetrically correct location. This term is sometimes used loosely to mean any photographic map produced by this process.
Digital Terrain Model (DTM)
A land surface represented in digital form by an elevation grid or lists of three-dimensional coordinates.
Embankments constructed of earth or other suitable materials to protect land from overflows or to regulate water.
Direct Diversions
The amount of water diverted from streams and rivers directly that is not withdrawn from storage in reservoirs.
Direct Mortality
The direct loss of fish associated with facilities (forebay, fish screens, and salvage facilities) for the south Delta export pumps. This direct mortality is a portion of the total fish mortality resulting from operation of the export pumps (see indirect morality).
Discharge Area
An area where the groundwater that has been recharged flows out of the aquifer under natural conditions or is removed from the aquifer by wells. See also recharge area.
Distribution System
System of ditches or conduits and their controls that conveys water from the supply canal to the farm points of delivery
The action of taking water out of a river system or changing the flow of water in a system for use in another location.
DLIS Archive
DLIS Archive page
Domestic Well
A water well used to supply water for the domestic needs of an individual residence or systems of four or fewer service connections.
Download Meeting Summary
Download Revised M N
DPIIC Accordion
draft delta plan
Draft EIR
Draft EIR Federal Agencies
Draft EIR Individuals
Draft EIR Local Agencies
Draft EIR Other Organizations
Draft EIR State Agencies
Draft EIR Tribal Governments
Draft PEIR Public Comments
Read public comments from State AgenciesRead public comments from Federal AgenciesRead public comments from Local AgenciesRead public comments from Tribal GovernmentsRead public comments from Other OrganizationsRead public comments from Individuals
Drainage Basin
See Watershed
Drinking Water Standards
State and federal regulations regarding water delivered by water purveyors that is used as a potable supply.
Drinking Water System
See Public Water System
Drinking Water Treatment and Distribution
Treatment is the physical, biological, and chemical processes that make water suitable for potable use. Distribution includes storage, pumping, and pipe systems to protect and deliver the treated water to customers.
Drip Irrigation
A method of micro irrigation wherein water is applied to the soil surface as drops or small streams through emitters. Discharge rates are generally less than 8 liters per hour (2 gallons per hour) for a single outlet emitters and 12 L/h (3 gal/h) per meter for line-source emitters.
Drought Condition
Hydrologic conditions during a defined period, greater than one dry year, when precipitation and runoff are much less than average.
Drought Conditions
A time when rainfall and runoff are much less than average. One method to categorize annual rainfall is as follows, with the last two categories being drought conditions: wet, above normal, below normal, dry critical.
Drought Preparedness
The magnitude and probability of economic, social or environmental consequences that would occur as a result of a sustained drought under a given study plan. Evaluation criteria measure the “drought tolerance” of study plans. Context: Water Management Objective
Drought Year Supply
The average annual supply of a water development system during a defined drought period.
Dry-Weather Runoff
Occurs when, for example, excess landscape irrigation water flows to the storm drain.
DSC Miscellaneous Correspondence
DSC Outgoing Correspondence
Dual Conveyance
A means of improving conveyance across the Delta by both improving through-Delta conveyance and isolating a portion of conveyance from Delta channels.
Dual Flood Zones
Flood insurance risk zones shown on a FIRM or DFIRM when (1) a levee-impacted area that is labeled as Zone AR also is subject to 1-percent-annual-chance flooding from a flooding source other than the source on the riverward side of the levee that causes the Zone AR flooding; or (2) some residual 1-percent-annual-chance flooding from the flooding source that causes the Zone AR flooding will remain even after the restoration project is complete. The flood insurance risk zone designations for dual flood zones are AR/A1-30, AR/AE, AR/AH, AR/AO, and AR/A.
Duty of Water
The total volume of irrigation water required to mature a particular type of crop. It includes consumptive use, evaporation, and seepage as well as the water returned to streams by percolation and surface water.
Early Action Meeting
Early Actions Meeting
Early Consultation
Economic Incentives
The total volume of irrigation water required to mature a particular type of crop. It includes consumptive use, evaporation, and seepage as well as the water returned to streams by percolation and surface water.
A recognizable, relatively homogeneous unit that includes organisms, their environment, and all the interactions among them.
Ecosystem Manager (Trustee)
An entity responsible for environmental improvements in the Bay-Delta system with the financial means, legal rights, authorities, and discretion needed to carry out the Ecosystem Restoration Program (ERP).
Ecosystem Restoration
Ecosystem Restoration
The activity of improving the condition of natural landscapes and biotic communities.
<p>--See <em>Bioregion</em></p>
Effective Date
The date on which the NFIP map for a community becomes effective and all sanctions of the NFIP apply.
Effective Map
The NFIP map issued by FEMA that is in effect as of the date shown in the title block of the map as “Effective Date,” “Revised,” or “Map Revised.”
Effective Porosity
The volume of voids or open spaces in alluvium and rocks that is interconnected and can transmit fluids.
Effective Precipitation
That portion of precipitation that supplies crop evapotranspiration. It includes precipitation stored in the soil before and during the growing season.
Effective Rooting Depth
The depth from which soil moisture is extracted; it is determined by the crop rooting characteristics and soil depth limitations.
Electrical Conductivity (EC)
The measure of the ability of water to conduct an electrical current, the magnitude of which depends on the dissolved mineral content of the water.
Elevated Building
A building that has no basement and has its lowest elevated floor raised above the ground level by foundation walls, shear walls, posts, piers, pilings, or columns. Solid foundation perimeter walls are not an acceptable means of elevating buildings in V and VE zones.
Elevation Certificate
A certificate that verifies the elevation data of a structure on a given property relative to the ground level. The Elevation Certificate is used by local communities and builders to ensure compliance with local floodplain management ordinances and is also used by insurance agents and companies in the rating of flood insurance policies.
Eligible Levee
A levee categorized as "active" in the U.S. Army Corps of Engineers (USACE) Rehabilitation and Inspection Program (RIP), for which USACE can provide assistance under Public Law 84-99 to repair damage caused by a flood event.
Emergency Phase
The phase of the NFIP that was implemented, on an emergency basis, to provide a first-layer amount of insurance on all insurable structures before the effective date of the initial FIRM/DFIRM.
Emergency Program
The initial phase of a community\s participation in the National Flood Insurance Program. During this phase, only limited amounts of insurance are available under the Act.
Emerging contaminants
See emerging pollutants
Emerging pollutants
Some unregulated chemicals and pollutants are being discovered to have unexpected health and environmental effects. Chemicals found in pharmaceuticals and personal care products, byproducts of fires and fire suppression, and discarded elements of nanotechnology are emerging as actual or potential water contaminants. Air deposition of a whole host of pollutants is now seen as a significant contributor to water pollution.
That portion of an elevated building below the lowest elevated floor that is either partially or fully shut-in by rigid walls.
Construction, placement of fill, or similar alteration of topography in the floodplain that reduces the area available to convey floodwaters.
Energy Availability
The energy consumption to facilitate water management-related actions such as desalting, pump-storage, groundwater extraction, conveyance or treatment. This criterion pertains to the economic feasibility of a proposed water management action in terms of operations and maintenance costs.
Energy Costs
Refers to the cost of energy use related to producing, conveying and applying water. It also refers to the cost of energy use for processes and inputs not directly related to water, but which can affect the demand for water (e.g., the cost of nitrogen fertilizer, tractor manufacturing).
Energy Production
Both instantaneous capacity (megawatt) and energy produced (kilowatt hours). Context: Evaluation Criteria.
The process of drawing fish into diversions along with water, resulting in the loss of such fish.
Environmental Water Account
A method of accounting for the water and financial assets that can be managed to provide additional protections for fishery resources beyond prescriptive standards.
Environmental Justice
The fair treatment of people of all races, cultures, and incomes with respect to the development, adoption, implementation, and enforcement of environmental laws, regulations, and policies. (Section 65040.12 (c) Government code)
Environmental Water
Minimum flow levels of a specific quality that is needed in order to assure the continued viability of fish and wildlife resources for a particular water body. This is water that is used to maintain and enhance the beneficial uses related to the preservation and enhancement of fish, wildlife, and other aquatic resources or preserves as specified in the Porter/Cologne Water Quality Control Act, 2008.
Environmental Water (flow based)
The amount of water dedicated to instream fishery uses, Wild and Scenic rivers, required and actual Sacramento-San Joaquin Delta outflow, and the Environmental Water Account.
Environmental Water (land based)
The amount of water used for fresh- and brackish-water managed wetlands and native vegetation.
Environmental Water Account
EWA is an element of the CALFED Bay-Delta Program’s overall management strategy for the Bay-Delta ecosystem. Its purpose is to project fish of the Bay-Delta Estuary through environmentally beneficial changes in the operations of the Central Valley Project and State Water Project.
Environmental Water Account(EWA)
Environmental Water Quality
Water quality in terms of ecosystem health, recreation, salinity intrusion, usability per sector, treatment costs, etc. Aquatic species and water bodies are vulnerable to changes to water quality.
ESA (Endangered Species Act)
Federal (FESA) and State (CESA) legislation that provides protection for species that are in danger of extinction.
ET (Reference Evapotranspiration)
The evapotranspiration rate from an extended surface of 3 to 6 inch (8 to 15cm) tall green grass cover of uniform height, actively growing, completely shading the ground, and not short on water (the reference ET reported by CIMIS).
See Evapotranspiration of Applied Water
Eutrophic Conditions
Body of water which has high primary productivity due to excessive nutrients and is subject to algal blooms resulting in poor water quality. Typically deficient in oxygen in the deeper regions of these waters ranging from hypoxic to anoxic. These conditions do not favor fish species that require or prefer cold, well oxygenated water such as trout.
Evaluation Criteria
The technical information that will be used to compare the favorability of different response packages of resource management strategies against future scenarios in California Water Plan Update 2009. They are designed to identify and measure potential effects on water supply, the environment, energy use or production, recreational opportunities, groundwater overdraft, and many more.
The physical process by which a liquid or solid is transformed to a gaseous state.
Evaporation and Evapotranspiration
- From Wastewater Urban – The portion of urban wastewater that either evaporates or is used by plants. - From Native Vegetation – The evaporation of precipitation from land surfaces and the evapotranspiration of precipitation by trees, brush, grass, and other plants. - From Unirrigated Ag – The evaporation of precipitation and the evapotranspiration of precipitation by dry-farmed crops. - From Wastewater Urban – The portion of urban wastewater that either evaporates or is used by plants.
Evaporation from Lakes
The annual surface evaporation from natural lakes.
Evaporation from Reservoirs
The annual surface evaporation from constructed surface water reservoirs.
Evaporative Demand
The collective influence of all climatic factors on the rate of evaporation of water.
ET is the amount of water transpired by plants, retained in plant tissues, and evaporated from plant tissues and surrounding soil surfaces (See also green water).
Evapotranspiration of Applied Water
ETAW is the amount of consumptive use by crops, landscapes, or other vegetation.
Event Products
Efficient water management practice.
Excess Delta Outflow
Freshwater outflow from the Sacramento-San Joaquin Delta that exceeds the amount required by law.
Water diversion from the Delta used for purposes outside the Delta.
Export-Inflow Ratio (E-IRatio)
This requirement presently limits Delta exports by the State and federal water projects to apercentage of Delta inflow. In July through January, 65% of inflow can be exported. During February through June, months most critical to fisheries, the allowable E-I ratio is reduced to 35% to help diminish reverse flows and the resulting entrainment of fish caused by south Delta export operations.
Extraction Wells
In the process of extracting groundwater for remediation, the groundwater flows through the aquifer(s) toward the extraction wells where it is removed for treatment.
Failure Breach
See Levee Failure Breach.
February 2010
February 2011
February 2012
February 2014
Federal Emergency Management Agency (FEMA)
The federal agency within the Department of Homeland Security that is tasked with responding to, planning for, recovering from, and mitigating against man-made and natural disasters.
Federal Policy Fee
A flat charge that the policyholder must pay on each new or renewal policy to defray certain administrative expenses incurred in carrying out the National Flood Insurance Program.
Federal Register
The document, published daily by the Federal Government, that presents regulation changes and legal notices issued by Federal agencies. FEMA publications in the Federal Register include Proposed, Interim, and Final Rules for BFE determinations; Compendium of Flood Map Changes, published twice each year; Final Rules concerning community eligibility for the sale of flood insurance; and Notices announcing clarifications of procedures and requirements.
Federally Authorized Levee System
A levee system that was designed and built by the U.S. Army Corps of Engineers in cooperation with a local sponsor and then turned over to that local sponsor to operate and maintain.
FEMA Levee Inventory System (FLIS)
A Web-based database and information retrieval system used by FEMA to collect and maintain information on structures shown on effective and soon-to-be-effective FIRMs/DFIRMs, including levees, dikes, floodwalls, and road and railroad embankments.
FEMA Map Assistance Center (FMAC)
A FEMA customer service center staffed by Map Specialists that are specially trained to answer specific questions about NFIP mapping and related issues, including: levee resources; status of active and completed studies/mapping projects, conditional and final map revision requests, and conditional and final map amendment requests; technical and administrative support data available from the FEMA archives. FMAC Map Specialists will link callers with other FEMA service and fax numbers and the FEMA Web site and provide information regarding, or copies of, FEMA products, brochures, and publications.
Soil that is brought in to raise the level of the ground. Depending on where the soil is placed, fill may change the flow of water or increase flood elevations. Fill may be used to elevate a building to meet NFIP requirements. Sometimes fill is combined with other methods of elevation such as pilings or foundation walls. Placement of fill requires a local permit from the community.
Final Draft Delta Plan
Final Draft Delta Plan
Read public comments from State AgenciesRead public comments from Federal AgenciesRead public comments from Local AgenciesRead public comments from Tribal GovernmentsRead public comments from Other OrganizationsRead public comments from IndividualsRead time extension requestsDelta Stewardship Council Public Hearing Transcripts All public comments except for time extension requests will not be available until after the comment period closes.
Final Draft Delta Plan comments from Federal Agencies
Final Draft Delta Plan comments from Individuals
Final Draft Delta Plan comments from Local Agencies
Final Draft Delta Plan comments from Other Organizations
Final Draft Delta Plan comments from State Agencies
Final Draft Delta Plan comments from Tribal Governments
Final Draft Delta Plan time extension requests
Final PEIR comments from Federal Agencies
Final PEIR comments from Individuals
Final PEIR comments from Local Agencies
Final PEIR comments from Other Organizations
Final PEIR comments from State Agencies
Final PEIR comments from Tribal Governments
Final Programmatic EIR
Final Programmatic EIR late arriving comments
Final Programmatic EIR late arriving
Final Programmatic Environmental Impact Report
Read public comments from State AgenciesRead public comments from Federal AgenciesRead public comments from Local AgenciesRead public comments from Tribal GovernmentsRead public comments from Other OrganizationsRead public comments from Individuals
Final Staff Draft Delta Plan
Read public comments received on the Final Staff Draft Delta Plan
Finished Water
Finished water is treated and/or conditioned to the point that it meets drinking water standards and is suitable for distribution to consumers for all potable water uses.
Firm Water Supply
The Central Valley Project Improvement Act Section 3406(d) (Refuge Water Supply) establishes the primary goal of providing a “firm water supply” for wildlife refuges. See firm-yield approach.
Firm-yield Approach
Deliver the same amount every year regardless of water supply conditions.
Fiscal Year
The 12-month period that begins on October 1 and ends on September 30.
Fish Entrainment
The incidental capture and loss of fish during water diversion.
Fish Salvage
The process of screening fish at the south Delta export facilities and physically transporting them by truck to release in other parts of the Delta. This generally results in higher fish mortality than a more conventional fish screen where screened fish simply return to the river and continue downstream. Fish salvage is required at the existing export facilities since there is no flow continuing downstream to carry the fish away.
Fish Screens
Physical structures placed at water diversion facilities to keep fish from getting pulled into the facility and dying there.
Flexible Operations
Operation of the south Delta export pumps that would allow reducing export pumping at times critical to fish and increasing export pumping at other times. Flexible operations would allow higher or lower export rates and export-inflow    ratios than prescribed by the 1995 Water Quality Control Plan. Pumping could deviate from currently permitted rates seasonally and on a real-time basis in response to Delta flows and fish distributions.
A general and temporary condition of partial or complete inundation of two or more acres of normally dry land area or of two or more properties (at least one of which is the policyholder\s property) from one of the following:1. Overflow of inland or tidal waters 2. Unusual and rapid accumulation or runoff of surface waters from any source 3. Mudflow 4. Collapse or subsidence of land along the shore of a lake or similar body of water as a result of erosion or undermining caused by waves or currents of water exceeding anticipated cyclical levels that result in a flood as defined above
Flood Disaster Protection Act (FDPA) of 1973
Made the purchase of flood insurance mandatory for the protection of property located in Special Flood Hazard Areas.
Flood Elevation Determination Docket (FEDD)
A file maintained by FEMA that includes all correspondence between FEMA and the community concerning a flood study; reports of meetings held among FEMA representatives, community representatives, the State NFIP Coordinator, private citizens, FEMA and community contractors, or other interested parties; relevant publications (e.g., newspaper notices, Federal Register notices); Letter of Final Determination; a copy of the Flood Insurance Study report; and a copy of the FIRM/DFIRM and Flood Boundary and Floodway Map.
Flood Event
A 100-year flood is the flood event having a 1 percent chance of being equaled or exceeded in any given year. A structure located within a special flood hazard area shown on a National Flood Insurance program may have a 26 percent chance of suffering flood damage during the term of a 30-year mortgage.
Flood Fight
The emergency measures used to prevent levee failure from seepage, erosion or overtopping during high water.
Flood Hazard Boundary Map (FHBM)
Official map of a community issued by the Federal Insurance Administrator, where the boundaries of the flood, mudflow, and related erosion areas having special hazards have been designated.
Flood Insurance Rate Map (FIRM)
The insurance and floodplain management map produced by FEMA that identifies, based on detailed or approximate analyses, the areas subject to flooding during a 1-percent-annual-chance flood event in a community. Flood insurance risk zones, which are used to compute actuarial flood insurance rates, also are shown. In areas studied by detailed analyses, the FIRM shows BFEs and/or base flood depths to reflect the elevations of the 1-percent-annual-chance flood. For many communities, when detailed analyses are performed, the FIRM also may show areas inundated by 0.2-percent-annual-chance (500-year) flood and regulatory floodway areas.
Flood Insurance Risk Zones
The zones, also referred to as “risk premium rate zones” and “flood insurance rate zones,” shown on a FIRM/DFIRM or FHBM that are used to determine flood insurance premium rates for properties in the community covered by the FIRM/DFIRM or FHBM. The flood insurance risk zones include Special Flood Hazard Areas (i.e., Zones A, A1-30, AE, A0, A99, AH, AR, AR/A, AR/A1-30, AR/AE, AR/A99, V, V1-30, VE, V0) and areas outside Special Flood Hazard Areas (i.e., Zones B, X, D, M, N, P, E).
Flood Insurance Study (FIS) Report
A document, prepared and issued by FEMA, that documents the results of the detailed flood hazard assessment performed for a community. The primary components of the FIS report are text, data tables, photographs, and Flood Profiles.
Flood irrigation
Method of irrigation where water is applied to the soil surface without flow controls, such as furrows, borders, or corrugations.
Flood Map Modernization (Map Mod)
The multiyear, congressionally supported initiative undertaken by FEMA to identify flood hazards, assess flood risks, and produce new or updated DFIRMs and FIS reports for floodprone communities throughout the United States.
Flood Profile
A graph showing the relationship of water-surface elevation to location, with the latter generally expressed as distance above the mouth for a stream of water flowing in an open channel.
Flood Protection Restoration Determination
A written determination by FEMA, issued to the CEO of a community, that the community has provided the data and documentation required by Section 65.14 of the NFIP regulations to show that the community is in the process of restoring a flood protection system (i.e., a levee system) that was constructed using Federal funds, recognized as providing 1-percent-annual-chance flood protection on an effective FIRM or DFIRM, and decertified by a Federal agency responsible for flood protection design or construction. The determination informs the community that FEMA will revise the effective FIRM or DFIRM to designated areas impacted by the system as a Special Flood Hazard Area designated Zone AR.
Flood Protection Restoration Project
A project undertaken by a community, alone or in cooperation with a sponsoring Federal agency, to restore a flood protection system (i.e., levee system) that was constructed using Federal funds, recognized as providing 1-percent-annual-chance flood protection on an effective FIRM or DFIRM, and decertified by a Federal agency responsible for flood protection design or construction. The intent of the completed project is to restore the system to providing at least a 1-percent-annual-chance level of flood protection.
Flood Protection System
Those physical works for which funds have been authorized, appropriated, and expended and which have been constructed specifically to modify flooding in order to reduce the extent of the area subject to a “special flood hazard” and the extent of the depths of the associated flooding. Flood protection systems typically include hurricane tidal barriers, dams, reservoirs, levees, or dikes.
Flood Risk
The magnitude and probability of consequences that would occur as a result of flood-induced infrastructure damage under a given study plan.
Any land area that is susceptible to being inundated by water from any source.
Floodplain Management
Actions designed to reduce risks to life, property, and the environment due to flooding. Actions can include watershed management, infrastructure construction and operation, variations in land use practices, floodway designations, etc. The operation of a program of corrective and preventative measures for reducing flood damage, including, but not limited to, emergency preparedness plans, flood-control works, and floodplain management regulations.
Floodplain Management Regulations
The zoning ordinances, subdivision regulations, building codes, health regulations, special-purpose ordinances, and other applications of enforcement used by a community to manage development in its floodplain areas.
Floodprone Area
See Floodplain.
Floodprone Community
Any community that is subject to inundation by the 1-percent-annual-chance flood.
A process for reducing or eliminating flood damage to a structure and/or its contents.
Anadromous Fish Restoration Program, part of the Central Valley Project Improvement Act. The AFRP identified instream and Delta flows needed for recovery of anadromous fish.
Gloria Gray
Governance and Implementation
Grassland Bypass Project
The Grasslands Bypass Project is a means of diverting selenium- contaminated agricultural drainage water away from fresh water channels serving Grassland wetlands. The project includes interim use of a 28-mile section of the San Luis Drain with strict monthly and annual selenium-load targets for discharges from the 97,000 acre project area.
Grizzly Bay
Groundwater Banking
Storing water in the ground for use to meet demand during dry years. In-lieu Groundwater Banking replaces groundwater used by users with surface water to build up and save underground water supply for use during drought conditions.
Hand Outs
Historical Records
A location on the Sacramento River in the northern Delta above the major tidal influence.  It has been identified as one potential location for a new diversion, if it is determined to be needed, from the Sacramento River. A new intake at this point could move more water into the central Delta or be the beginning for an isolated facility. Sacramento River water is much fresher at this location than at the export facilities and a diversion at this point may have substantially fewer impacts on most species of fish than the current diversions at the export pumps.  
How we do it
A chart or graph showing the change in flow over time for a particular stream or river.
Channel modification (channelization), flow alterations, levees, and dams. Hydrology
A geologic framework consisting of a body of rock having considerable lateral extent and composing a reasonably distinct hydrologic system.
Hyporheic Zone
The region of saturated sediments beneath and beside the active channel and that contain some proportion of surface water that was part of the flow in the surface channel and went back underground and can mix with groundwater.
Hypoxic Zone
Salt becomes too concentrated, nutrient salts become excessive.
In-Delta Storage
Water storage within the Delta by converting an existing island to a reservoir. The storage can help facilitate flexible operations of the export pumps by allowing export of stored water when critical fish species are present in the south Delta.      
In-lieu Recharge
The practice of providing surplus surface water to historical groundwater users, thereby leaving groundwater in storage for later use. (cf. groundwater recharge)
Increased Cost of Compliance (ICC)
Coverage for expenses a property owner must incur, above and beyond the cost to repair the physical damage the structure actually sustained from a flooding event, to comply with mitigation requirements of state or local floodplain management ordinances or laws. Acceptable mitigation measures are elevation, flood-proofing, relocation, demolition, or any combination thereof.
Indefinite Delivery/Indefinite Quantity Contractor (IDIQ)
An architectural and engineering firm or a Federal, State, or local agency that performs flood hazard studies under contract with FEMA as part of Flood Map Modernization.
Independent Review
Indirect Mortality
The indirect fish losses from operating the Delta Cross Channel and south Delta export pumps. For example, fish diverted from the Sacramento River into the central and south Delta experience higher mortality through increased stress, small agricultural water diversions, poor water quality, predation, reduced shallow water habitat for fry, higher water temperatures, and higher residence times. This indirect mortality is a portion,of the total fish mortality resulting from operation of the export pumps (see direct morality).
Indirect Reuse
When a downstream entity withdraws water from a stream and a portion of that water is wastewater from an upstream discharge that has commingled with the ambient streamflow, the reuse is termed indirect reuse.
Industrial Activity Mix
The mix of high and low water using industrial activity. Note that Industrial Activity is broken into two factors: Total Industrial Activity and Industrial Activity Mix. The latter factor allows designation of the type of industry that is occurring. This is necessary to account for the large variation in water demands by industry type. See also total industrial activity.
The flow of water downward from the land surface into and through the upper soil layers.
Infiltration Basin
A shallow basin designed to infiltrate storm water into the ground.
Infiltration Capacity
The maximum rate at which infiltration can occur under specific conditions of soil moisture.
Inflow from Mexico
The New River and Alamo River inflows from Mexico.
Inflow from Oregon
Klamath River inflow from Oregon.
<p>The underlying foundation or basic framework of a system, For water, this includes the canals, pipelines, pumps, reservoirs, and treatment plants that make up the treatment and delivery system.<br /><br /></p> <p><a href="#top">Back to top</a></p>
Injection Wells
<p>Injection wells are used primarily to recharge confined aquifers. The design of an injection well for artificial recharge is similar to that of a water supply well. The principal difference is that waterflows from the injection well into the surrounding aquifer under either a gravity head or a head maintained by an injection pump. <br /><br /></p> <p><a href="#top">Back to top</a></p>
Instream Environmental
<p>Instream flows used only for environmental purposes.</p> <p><br /><a href="#top">Back to top</a></p>
Instream Flow Net Water Use
<p>The use of water within its natural watercourse as specified in an agreement, water rights permit, court order, FERC license, or other State or federal requirement.</p> <p><br /><a href="#top">Back to top</a></p>
Instream Flows
<p>The use of water within its natural watercourse as specified in an agreement, water rights permit, court order, FERC license, etc. They support natural ecosystems, create habitat for plants and animals, and may provide additional benefits such as recreation. See also required instream flows.</p> <p><br /><a href="#top">Back to top</a></p>
Instream Recharge
<p>Allows water to percolate through the streambed itself.</p> <p><br /><a href="#top">Back to top</a></p>
Instream Uses
<p>The beneficial uses of water within a stream for river without diversion from the stream.</p> <p><br /><a href="#top">Back to top</a></p>
Integrated Flood Management
<p>IFM is a comprehensive approach to flood management that considers land and water resources at a watershed scale within the context of integrated water management; employs both structural and non-structural measures to maximize the benefits of floodplains and minimize loss of life and damage to property from flooding; and recognizes the benefits to ecosystems from periodic flooding.</p> <p><br /><a href="#top">Back to top</a></p>
Integrated On-farm Drainage Management
<p>IFDM is an integrated agricultural water management system that applies subsurface drainage water to a sequence of increasingly salt-tolerant crops.</p> <p><br /><a href="#top">Back to top</a></p>
Integrated Regional Water Management
<p>A multi-objective approach that encourages using a mix of resource management strategies to provide benefits to regions.</p> <p><br /><a href="#top">Back to top</a></p>
Integrated Water Resources Information System
<p>IWRIS, released by DWR in 2008, is the first centralized groundwater data management system developed to help local and regional water management entities integrate and analyze existing data about their groundwater system and potential value of current groundwater management in their integrated planning processes. It serves as a centralized information system for accessing the data about groundwater as well as groundwater management and some DWR grant program funding statewide. See also Water PIE.</p> <p><br /><a href="#top">Back to top</a></p>
Interagency Coordinated Program
<p>A cooperative effort among the California Department of Fish and Game, the U.S. Bureau of Reclamation, the U.S. Fish and Wildlife Service, and the Grasslands Water District to develop optimum water use planning for managed wetlands of the Central Valley.</p> <p><a href="#top">Back to top</a></p>
<p>The simultaneous planting of two or more crops in the same field. The practice is used to help control pest populations that can occur on monoculture crops, sometimes called ÒpolycroppingÓ or Òplant stratification.Ó</p> <p><br /><a href="#top">Back to top</a></p>
<p>Smaller watersheds or areas outside of the larger watershed boundaries used at the regional planning scale.</p> <p><br /><a href="#top">Back to top</a></p>
Interim Plan
Interim Plan
Read public comments received on the Interim Plan
Interim Plan
Interim Science Action Agenda
<p>This is for the Interim Science Action Agenda pages accordion.</p>
Interior Drainage
<p>Natural or modified outflow of streams within a levee-impacted area for the conveyance of runoff. <br /><br /><br /></p> <p><a href="#top">Back to top</a></p>
Interior Drainage Systems
<p>Systems associated with levee systems that usually include storage areas, gravity outlets, pumping stations, or a combination thereof.</p> <p><br /><a href="#top">Back to top</a></p>
Interregional Import Projects
<p>Movement of water between regions through mechanisms such as the State and federal water projects.</p> <p><br /><a href="#top">Back to top</a></p>
<p>An interconnection permitting passage of utility service (water, electricity) between two or more systems such as electric and water utility systems.</p> <p><br /><a href="#top">Back to top</a></p>
Invasive Species
<p>Non-indigenous plants or animals that adversely affect the habitats they invade economically, environmentally, or ecologically.</p> <p><br /><a href="#top">Back to top</a></p>
Ion Exchange
<p>Processes of purification, separation, and decontamination of aqueous and other ion-containing solutions with solid ion exchangers such as sodium carbonate used for water softening.</p> <p><br /><a href="#top">Back to top</a></p>
Irrecoverable Water
<p>The amount of applied water that flows to or percolates to a salt sink, is used by the growth process of plants (evapotranspiration), or evaporates from a conveyance facility or drainage canal. See recoverable water</p> <p><br /><a href="#top">Back to top</a></p>
Irrigation Efficiency (IE)
<p>The efficiency of water application and use, calculated by dividing a portion of applied water that is beneficially used by the total applied water, expressed as a percentage The two main beneficial uses are crop water use (evapotranspiration, ETc) and leaching to maintain a salt balance.</p> <p><br /><a href="#top">Back to top</a></p>
Irrigation Water Requirements
<p>The quantity of water exclusive of precipitation that is required from various uses.</p> <p><br /><a href="#top">Back to top</a></p>
ISB Meeting
ISB Products
Isolated Conveyance Facility
<p>A canal or pipeline that transports water between two different locations while keeping it separate from Delta water.</p> <p><a href="#top">Back to top</a></p>
January 2010
January 2011
January 2012
Joint Powers Agreement (JPA)
<p>An agreement entered into by two or more public agencies that allows them to jointly exercise any power common to the contracting parties. JPA is defined in Ch. 5 (commencing with Section 6500) of Division 7 of Title 1 of the California Government Code.</p> <p><br /><a href="#top">Back to top</a></p>
July 2010
July 2011
July 2012
July 2013
July 2014
July 2015
June 2010
June 2011
June 2013
Key Document
<p>Keyline systems of water and soil conservation were developed in Australia during the 1950s by P.A. Yeomans as a response to increasing desertification and erosion of the landscape. Keyline agriculture is a permaculture farming technique offering holistic farm design. Keyline is a set of principles, techniques, and systems, which coordinate into a development plan for rural and urban landscapes. The result is a strategic master plan to develop the natural or existing landscape through regeneration and enhancement. On Keyline properties the typical vistas are of lakes with water birds, roads along the contours and ridge lines, contour tree belts, healthy crops and green pasture growing in dark biologically fertile soil.</p> <p><br /><a href="#top">Back to top</a></p>
<p>Natural lakes, ponds and human-made reservoirs ecosystems.</p> <p><br /><a href="#top">Back to top</a></p>
Land Fallowing/Retirement
<p>Allowing previously irrigated agricultural land to temporarily lie idle (fallowing) or purchasing such land and allowing it to remain out of production for a variety of purposes for a long period of time.</p> <p><a href="#top">Back to top</a></p>
Land Subsidence
<p>The lowering of the natural land surface due to groundwater (or oil and gas) extraction.</p> <p><br /><a href="#top">Back to top</a></p>
Latest Delta Plan Draft
Law of Demand
<p>People will purchase less of a good or service as its price increases.</p> <p><br /><a href="#top">Back to top</a></p>
Leaching Efficiency
<p>The ratio of the average salt concentration in drainage water to an average salt concentration in the soil water of the root zone when near field capacity.</p> <p><br /><a href="#top">Back to top</a></p>
Leaching Requirements
<p>The fraction of water entering the soil that must pass through the root zone in order to prevent soil salinity from exceeding a specific value.</p> <p><br /><a href="#top">Back to top</a></p>
Lead Scientist Recruitment
Leaky Confining Layer
<p>A low-permeability layer that can transmit water at sufficient rates to furnish some recharge from an adjacent aquifer to a well.</p> <p><br /><a href="#top">Back to top</a></p>
Legacy Pollutants
<p>Examples are mercury, extracted from the Coast Range and used to process gold in the Sierra Nevada mines in the 19th century; industrial chemicals such as polychlorinated biphenyls (PCBs), used in electrical transformers; and pesticides such as dichloro-diphenyl-trichloroethane (DDT).</p> <p><br /><a href="#top">Back to top</a></p>
Legally Defined Parcel of Land
<p>A parcel of land for which a metes and bounds description or a plat has been recorded. Structure may exist on legally defined parcels of land.</p> <p><br /><a href="#top">Back to top</a></p>
Letter of Final Determination (LFD)
<p>The letter in which FEMA announces its final determination regarding the flood hazard information, including (when appropriate) BFEs or base flood depths, presented on a new or revised DFIRM and FIS report. By issuing the LFD, FEMA begins the compliance period and establishes the effective date for the new or revised DFIRM and FIS report.</p> <p><br /><a href="#top">Back to top</a></p>
Letter of Map Change
<p>A collective term used to describe official amendments and revisions to National Flood Insurance maps that are accomplished by a cost-effective administrative procedure and disseminated by letter.</p> <p><br /><a href="#top">Back to top</a></p>
<p>A man-made structure, usually an earthen embankment, designed and constructed in accordance with sound engineering practices to contain, control, or divert the flow of water so as to provide protection from temporary flooding.</p> <p><br /><a href="#top">Back to top</a></p>
Levee Breach
<p>A rupture, break, or gap in a levee system that causes flooding in the adjacent area and whose cause has not been determined.</p> <p><br /><a href="#top">Back to top</a></p>
Levee Crevasse
<p>A crack or breach in a levee that causes flooding in the adjacent area.</p> <p><br /><a href="#top">Back to top</a></p>
Levee Failure Breach
<p>A rupture, break, or gap in a levee system that causes flooding in the adjacent area and for which a cause of failure is both known and occurred without overtopping. An investigation is usually required to determine the cause.</p> <p><br /><a href="#top">Back to top</a></p>
Levee Overtopping
<p>&nbsp;</p> <p>Floodwater levels that exceed the crest elevation of a levee system and flow into levee-impacted areas landward of the levee system. <br /><br /><a href="#top">Back to top</a></p>
Levee Overtopping Breach
<p>A rupture, break, or gap in a levee system that causes flooding in the adjacent area and whose cause is known to be a result of overtopping. <br /><br /><br /><a href="#top">Back to top</a></p>
Levee Owner
<p>A Federal or State agency, a water management or flood control district, a local community, a levee district, a nonpublic organization, or an individual considered the proprietor of a levee. <br /><br /><br /><br /><a href="#top">Back to top</a></p>
Levee System
<p>A flood protection system that consists of a levee, or levees, and associated structures, such as closure and drainage devices, which are constructed and operated in accordance with sound engineering practices. <br /><br /><br /><br /><br /><a href="#top">Back to top</a></p>
Levee-Impacted Area
<p>The floodplain area landward of a levee system for which the levee system provides some level of flood protection or risk reduction.</p> <p><br /><a href="#top">Back to top</a></p>
Liberty Island
Lines of Protection
<p>Locations of levees or walls that prevent floodwaters from entering an area.<br /><br /><br /><br /><br /><br /><a href="#top">Back to top</a></p>
Lithologic Log
<p>A record of the lithology of the soils, sediments and/or rock encountered in a borehole from the surface to the bottom.<br /><br /><a href="#top">Back to top</a></p>
<p>The description of rocks, especially in hand specimen and in outcrop, on the basis of such characteristics as color, mineralogic composition, and grain size.<br /><br /><br /><a href="#top">Back to top</a></p>
<p>Long-term Operations Biological Opinions</p>
Local Deliveries
<p>The amount of water delivered by local water agencies and individuals. It includes direct deliveries of water from streamflows, as well as local water storage facilities. Also includes water supply for&nbsp; Instream and Wild and Scenic River flowsÑa change from Update 2005 wherein there was a separate category for Dedicated Environmental Water. <br /><br /><br /><br /><a href="#top">Back to top</a></p>
Local Imports
<p>The amount of water transferred by local agencies from other regions of the state. <br /><br /><br /><br /><br /><a href="#top">Back to top</a></p>
Local Newspaper
<p>The community newspaper, identified by the Chief Executive Officer (CEO) or other designated community official, in which FEMA publishes notices at the beginning of a Mapping project, at the beginning of the appeal period, and at other times during the processing of a new or revised FIRM when required. <br /><br /><br /><br /><br /><br /><a href="#top">Back to top</a></p>
Local Sponsor
<p>See Public Sponsor.<br /><br /><br /><br /><br /><br /><br /><a href="#top">Back to top</a></p>
<p>Long-term Operations Opinions Annual Review</p>
<p>A parcel of land for which a metes and bounds description or a plat has been recorded and on which one or more structures may be built.<br /><br /><br /><a href="#top">Back to top</a></p>
Low Impact Development
<p>LID uses site design and storm water management to maintain the siteÕs predevelopment runoff rates and volumes. Design techniques filtrate, filter, store, evaporate, and detain runoff close to the source of rainfall. LID can be used to benefit water quality, address the modifications to the hydrologic cycle, and be a means to augment local water supply through either infiltration or water harvesting. LID is seen in California as an alternative to conventional storm water management. <br /><br /><br /><br /><a href="#top">Back to top</a></p>
Lowest Adjacent Grade (LAG)
<p>The lowest natural elevation of the ground surface next to a structure. <br /><br /><br /><br /><br /><a href="#top">Back to top</a></p>
Lowest Finished Floor Elevation (LFFE)
<p>The lowest floor of the lowest enclosed area (including basement) of a structure.<br /><br /><br /><br /><br /><br /><a href="#top">Back to top</a></p>
Lowest Floor
<p>The lowest floor of the lowest enclosed area (including a basement). An unfinished or flood-resistant enclosure, usable solely for parking of vehicles, building access, or storage in an area other than a basement area, is not considered a building\s lowest floor provided that such enclosure is not built so as to render the structure in violation of requirements.<br /><br /><br /><br /><br /><br /><br /><a href="#top">Back to top</a></p>
<p>An abbreviation for million acre feet, as in 2 MAF or 2,000,OOOAF.; 10,000 cfs flowing for a year is about 7 MAF.</p> <p><a href="#top">Back to top</a></p>
Management Cues
March 2010
March 2011
March 2014
March and April 2012
May 2010
May 2011
May 2013
May and June 2012
May and June 2015
May June 2014
Meander Belt
<p>Protecting and preserving land in the vicinity of a river channel in order to allow the river to meander. Meander belts are a way to allow the development of natural habitat around ariver.</p> <p><a href="#top">Back to top</a></p>
Media Advisory
Media Advisory
Meeting Advisory
Meeting Agenda Material
Meeting Agenda Materials
Meeting doc
Meeting Docs
Meeting Documents
Meeting Notice
Meeting Notice Delta ISB
Meeting Notice DSC - Council Meeting
Meeting Notice DSC - Delta Plan Implementation Committee Meeting
Meeting Notice DSC - Workshop
Meeting Notice Science - Review Event
Meeting Notice Science - Seminar
Meeting Notice Science - Workshop
Meeting Notices
Meeting Summary DSC - Council Meeting
Meeting Summary DSC - Council Meeting
Merced CA
Millennium Ecosystem Assessment
Mine Drainage Remediation
<p>Controlling or treating polluted drainage from abandoned mines.</p> <p><a href="#top">Back to top</a></p>
Modified Rulemaking comments from Federal Agencies
Modified Rulemaking comments from Individuals
Modified Rulemaking comments from late arriving letters
Modified Rulemaking comments from Local Agencies
Modified Rulemaking comments from Other Organizations
Modified Rulemaking comments from State Agencies
Modified Rulemaking comments from Tribal Governments
Modified Rulemaking Process
Read public comments from State AgenciesRead public comments from Federal AgenciesRead public comments from Local AgenciesRead public comments from Tribal GovernmentsRead public comments from Other OrganizationsRead public comments from IndividualsRead public comments on late arriving letters All public comments except for time extension requests will not be available until after the comment period closes.
News Clip
News Clips
News Release
Non-Native Species
<p>Also called introduced species or exotic species; refers to plants and animals that originate elsewhere and are brought into a new area, where they may dominate the local species or in some way negatively impact the environment for native species.</p> <p><a href="#top">Back to top</a></p>
Notice of Preparation
Read public comments received on the Notice of Preparation
Notice of Preparation
November 2010
November 2011
November 2012
November 2014
October 2010
October 2011
October 2012
October 2014
Old River
<p>A natural channel in the southern Delta. The channel merges with many other channels in the south Delta, passesby the south Delta export facilities and connects with the San Joaquin River at its upstream end. Much of the water approaching the export facilities flows up Old River from the central Delta. Potential improvements to the channel include a fish barrier at its upstream end to keep migrating fish in the San Joaquin River and dredging north of Clifton Court Forebay to allow more efficient flow to the export facilities.</p> <p><a href="#top">Back to top</a></p>
Op Ed
Other Correspondence
Other Correspondence
Read other correspondence with the Council
Other Correspondence
Over Draft
<p>The condition, over the long-term, when more water is withdrawn from a groundwater basin than is recharged.</p> <p><a href="#top">Back to top</a></p>
Panel Discussion
Performance Measures
Performance Measures Archives Page
Performance Measures Archives Page
Press release
Press Releases
Press Releases
Primary Docs Reviewed
Program Element
<p>The program elements for the Phase II Alternatives include an element for Delta conveyance, a element for storage, and the six common program elements ( Water Use Efficiency, Water Quality, Levee System Integrity, Ecosystem Restoration, Water Transfers, and Watershed Management).</p> <p><a href="#top">Back to top</a></p>
Proposed Final Delta Plan
Proposed Final Delta Plan late arriving comments
Proposed Final Delta Plan late arriving
Proposed Final Draft Delta Plan
Read public comments received on the Proposed Final Draft Delta Plan
Prospect Island
Public Comment
Public Comments
Public Workgroups
Read public comments received on the public workgroups
Public Workgroups
<p>A broad indication of the net direction and quantity of flow in the San Joaquin River at Jersey Point. This is only an indicator since net flow is not measurable at this location. Considerable tidal exchange at this point is not included, because QWEST is an estimate of net flow conditions. A positive QWEST indicates the net flow is generally in the downstream direction towards the San Francisco Bay. A negative number indicates that the net flow is generally in the upstream direction to the east. Generally, a positive QWEST is desirable for Delta flow circulation, water quality, and fisheries.</p> <p><a href="#top">Back to top</a></p>
Real-Time Monitoring and Operations
<p>Continuous observation in multiple locations of biological conditions on site in order to improve management to protect fish species and allow optimal operation of the water supply system. This is an essential feature to allow flexible operations of the export pumps.</p> <p><a href="#top">Back to top</a></p>
Recirculated DPEIR comments from Federal Agencies
Recirculated DPEIR comments from Individuals
Recirculated DPEIR comments from late arriving letters
Recirculated DPEIR comments from Local Agencies
Recirculated DPEIR comments from Other Organizations
Recirculated DPEIR comments from State Agencies
Recirculated DPEIR comments from Tribal Governments
Recirculated DPEIR time extension requests
Recirculated Draft Programmatic EIR
Recirculated Draft Programmatic Environmental Impact Report
Read public comments from State AgenciesRead public comments from Federal AgenciesRead public comments from Local AgenciesRead public comments from Tribal GovernmentsRead public comments from Other OrganizationsRead public comments from IndividualsRead time extension requestsDelta Stewardship Council Public Hearing TranscriptsRead public comments on late arriving letters All public comments except for time extension requests will not be available until after the comment period closes.
Recommended Readings
Reference Materials
<p>The land adjacent to a natural water course such as a river or stream. Often supports vegetation that provides important wildlife habitat, and important fish habitat values when growing large enough to overhang the bank.</p> <p><a href="#top">Back to top</a></p>
Risk Reduction
<p>Habitat within or alongside a river or channel.</p> <p><a href="#top">Back to top</a></p>
Rulemaking comments from Federal Agencies
Rulemaking comments from Individuals
Rulemaking comments from Local Agencies
Rulemaking comments from Other Organizations
Rulemaking comments from State Agencies
Rulemaking comments from Tribal Governments
Rulemaking Process
Rulemaking Process
Read public comments from State AgenciesRead public comments from Federal AgenciesRead public comments from Local AgenciesRead public comments from Tribal GovernmentsRead public comments from Other OrganizationsRead public comments from IndividualsRead time extension requestsDelta Stewardship Council Public Hearing Transcripts All public comments except for time extension requests will not be available until after the comment period closes.
Rulemaking Time extension requests
Sacramento CA
Sacramento River
Salmonoids and other kinds of Fish Species
San Francisco Bay
San Francisco Estuary and Watershed Science
San Joaquin River
San Joaquin Valley Drainage Program
<p>The Federal-State San Joaquin Valley Drainage Program (SJVDP) studied ways of remedying subsurface agricultural drainage and related problems operated during the period 1985-1990. The SJVDP prepared the report titled “A Management Plan for Agricultural Subsurface Drainage and Related Problems on the Westside of the San Joaquin Valley, September 1990.” The report identified the need for 75,000 acres of land retirement by year 2040 but pointed out that without adequate drainage management, soil salinization will occur and potentially cause almost 500,000 acres of land to be abandoned by year 2040.</p> <p><a href="#top">Back to top</a></p>
Science Program
Science Program Product
Science PSP project
Scoping Meeting
Scoping Meetings
September 2010
September 2011
September 2012
September 2014
September 2015
Setback Levee
<p>A constructed embankment to prevent flooding that is positioned some distance from the edge of the river or channel. Setback levees allow wildlife habitat to develop between the levee and the river or stream.</p> <p><a href="#top">Back to top</a></p>
Shallow Water
<p>Water with just enough depth to allow for sunlight penetration, plant growth, and the development of small organisms that function as fish food. Serve as spawning areas for delta smelt.</p> <p><a href="#top">Back to top</a></p>
Sherman Island
Significant Communication
<p>A young salmon that has assumed the silvery color of the adult and is ready to migrate to the sea.</p> <p><a href="#top">Back to top</a></p>
Solution Principles
<p>Fundamental principles that guide the development and evaluation of Program alternatives. They provide an overall measure of acceptability of the alternatives.</p> <p><a href="#top">Back to top</a></p>
South of Delta Storage
<p>Water storage supplied with water exported south from the Delta.</p> <p><a href="#top">Back to top</a></p>
Speeches / Presentations / Panels
Staff Draft Delta Plan
Staff Recommendations
State Coordinating Agency
See State National Flood Insurance Program (NFIP) Coordinator. <p><a href="#top">Back to top</a></p>
State National Flood Insurance Program (NFIP) Coordinator
The agency of the State government, or other office designated by the Governor of the State or by State statute at the request of FEMA to assist in the implementation of the NFIP in that State. <p><a href="#top">Back to top</a></p>
State Plane Coordinates
A system of X,Y coordinates defined by the U.S. Geological Survey for each state. Locations are based on the distance from an origin within each State. <p><a href="#top">Back to top</a></p>
State Water Project
<p>A California state water storage and conveyance system that pumps water from the Delta for agricultural, urban domestic, and industrial purposes. The SWP was authorized by legislation in 1951.</p> <p><a href="#top">Back to top</a></p>
Statewide Water Management Systems
These include physical facilities (more than 1,200 State, federal, and local reservoirs, as well as canals, treatment plants, and levees), which make up the backbone of water management in California, and statewide water management programs, which include water-quality standards, monitoring programs, economic incentives, water pricing policies, and statewide water efficiency programs such as appliance standards, labeling, and education. <p><a href="#top">Back to top</a></p>
Statutory Permitting System
Water rights permitting system defined in the California Water Code and administered by the State Water Resources Control Board. <p><a href="#top">Back to top</a></p>
Stillwater Flood Elevation (SWEL)
Projected elevation that flood waters would assume, referenced to National Geodetic Vertical Datum of 1929, North American Vertical Datum of 1988, or other datum, in the absence of waves resulting from wind or seismic effects. <p><a href="#top">Back to top</a></p>
Stillwater Flood Level (SWFL)
Rise in the water surface above normal water level on the open coast due to the action of wind stress and atmospheric pressure on the water surface. <p><a href="#top">Back to top</a></p>
Stochastic Simulation
This is also known as Monte Carlo simulation or model sampling. An example of this type of analysis is the US Army Corps of EngineerÕs software program, HEC-FDA (Flood Damage Assessment) that directly incorporates uncertainties into a flood damage analysis. <p><a href="#top">Back to top</a></p>
Stockton CA
Logs, planks, cut timber, steel, or concrete beams fitting into end guides between walls or piers to close openings in levees, floodwalls, dams, or other hydraulic structures. <p><a href="#top">Back to top</a></p>
Storm Water (Runoff)
Water which is originated during a precipitation event which may collect and concentrate diffused pollutants and carry them to water courses causing degradation. Runoff in the urban environment, both storm-generated and dry weather flows, has been shown to be a significant source of pollutants to the surface waters of the nation. In California, the authority to regulate urban and storm water runoff under the NPDES system has been delegated by EPA to the State Water Resources Control Board and the nine Regional Water Quality Control Boards. See Volume 2, Chapter 19 Urban Runoff Management RMS <p><a href="#top">Back to top</a></p>
Strategic Plan
The long-term goals of an organization or program and an outline of how they will be achieved (e.g., adopting specific strategies, approaches, and methodologies). <p><a href="#top">Back to top</a></p>
The science of rocks. It is concerned with the original succession and age relations of rock strata and their form, distribution, lithologic composition, fossil content, geophysical and geochemical propertiesÑall characters and attributes of rocks as strataÑand their interpretation in terms of environment and mode of origin and geologic history. <p><a href="#top">Back to top</a></p>
Stream Order
Refers to a systematic process for describing the degree of branching of a stream network within a watershed. <p><a href="#top">Back to top</a></p>
Street Gates
Closure gates used during flood periods to close roadway openings through levees or floodwalls. <p><a href="#top">Back to top</a></p>
For floodplain management purposes, walled and roofed buildings, including gas or liquid storage tanks that are principally above ground, as well as manufactured homes. For flood insurance purposes, walled and roofed buildings, other than a gas or liquid storage tanks, that are principally above ground and affixed to permanent sites, as well as a manufactured homes on a permanent foundation. <p><a href="#top">Back to top</a></p>
Study Contractor (SC)
See Indefinite Delivery Indefinite Quantity Contractor (IDIQ). <p><a href="#top">Back to top</a></p>
Study/Mapping Project
Any activity undertaken by FEMA, separately or in partnership with a mapping partner, to create a new or updated DFIRM, including detailed engineering studies, approximate engineering studies, and floodplain boundary redelineations based on updated topographic information. <p><a href="#top">Back to top</a></p>
Subcritical Flow
Flow with a mean velocity that is less than the critical velocity; in other words, tranquil flow. <p><a href="#top">Back to top</a></p>
Application of irrigation water below the ground surface by raising the water table to within or near the root zone. <p><a href="#top">Back to top</a></p>
Levees that are built for the purpose of underseepage control. Sublevees encircle areas impacted by the main levee that are subject, during high-water stages, to high uplift pressures and possibly the development of sand boils. Sublevees normally tie into the main levees, thus providing a basin that can be flooded during high-water stages. Sublevees are rarely employed as the use of relief wells or seepage berms make them unnecessary except in emergencies. <p><a href="#top">Back to top</a></p>
An application for flood insurance on a building for which no risk rate is published in the Flood Insurance Manual. Insurance coverage can be obtained only after the NFIP has approved the application and has established the risk premium rate. <p><a href="#top">Back to top</a></p>
Submitted Applications
See land subsidence <p><a href="#top">Back to top</a></p>
Substantial Improvement
Any reconstruction, rehabilitation, addition, or other improvement of a structure, the cost of which equals or exceeds 50 percent of the market value of the structure before the start of the construction of the improvement. <p><a href="#top">Back to top</a></p>
Subsurface Drip Irrigation
Application of water below the soil surface through emitters, with discharge rates generally in the same range as drip irrigation. This method of water application is different from and not to be confused with subirrigation where the root zone is irrigated by water table control. <p><a href="#top">Back to top</a></p>
Subterranean Stream
Subterranean streams Òflowing through known and definite channelsÓ are regulated by CaliforniaÕs surface water rights system. The physical conditions that must be present in a subterranean stream flowing in a known and definite channel are: (1) a subsurface channel must be present; (2) the channel must have relatively impermeable bed and banks; (3) the course of the channel must be known or capable of being determined by reasonable inference; and (4) groundwater must be flowing in the channel. <p><a href="#top">Back to top</a></p>
Suisun Marsh
Supercritical Flow
Flow with a mean velocity that is greater than the critical velocity; in other words, rapid flow. <p><a href="#top">Back to top</a></p>
Supplemental Meeting Material
Surface Irrigation
Irrigation in which the soil surface is used as the conduit, as in furrow and border irrigation, and as opposed to sprinkler, drip, and subirrigation. <p><a href="#top">Back to top</a></p>
Surface Storage
Uses reservoirs to collect water for later release and use. <p><a href="#top">Back to top</a></p>
Surface Storage Facilities
The volume and yield of usable reservoir storage in a given area. <p><a href="#top">Back to top</a></p>
Surface Supply
Water supply obtained from streams, lakes, and reservoirs. <p><a href="#top">Back to top</a></p>
Surface Water
As defined under the California Surface Water Treatment Rule, CCR, Title 22, Section 64651.83, means Òall water open to the atmosphere and subject to surface runoff..." and hence would include all lakes, rivers, streams and other water bodies. Surface water thus includes all groundwater sources that are deemed to be under the influence of surface water (i.e., springs, shallow wells, wells close to rivers), which must comply with the same level of treatment as surface water. <p><a href="#top">Back to top</a></p>
Surface Water Net Change in Storage
The difference between the water released from and water flowing into surface reservoirs. <p><a href="#top">Back to top</a></p>
Surface Water Storage-End of Year
The amount of water stored in lakes and reservoirs at the end of the water year. <p><a href="#top">Back to top</a></p>
Surface Water Total Available Storage
Total developed surface storage available in a region. <p><a href="#top">Back to top</a></p>
Surge Irrigation
A surface irrigation technique wherein flow is applied to furrows (or less commonly, borders) intermittently during a single irrigation set. <p><a href="#top">Back to top</a></p>
Surplus Water
Water that is not being used directly or indirectly to benefit the environmental, agricultural or urban use sectors. <p><a href="#top">Back to top</a></p>
(1) The intent in Water Plan Update 2009 when discussing sustainable development or sustainable use of resources is to portray the concepts of longevity and resilience. A system that is sustainable should meet todayÕs needs without compromising this ability of future generations to meet their own needs. A sustainable system generally provides for the economy, ecosystem, and social equity. (2) A specific resource that avoids complete depletion over a specified time horizon. The continued feasibility of a specified economic activity over a specified time horizon, usually influenced by management and policy actions. <p><a href="#top">Back to top</a></p>
Sustainable Development
See sustainability. <p><a href="#top">Back to top</a></p>
System Reoperation
Changing existing water system operation and management procedures or priorities to either meet competing beneficial uses or derive more total benefits from the water system by operating more efficiently. <p><a href="#top">Back to top</a></p>
<p>Thousand acre feet, as in 125 TAF equals 125,000 AF.</p> <p><a href="#top">Back to top</a></p>
Surface runoff water from irrigated agriculture. <p><a href="#top">Back to top</a></p>
Technically Incorrect Base Flood Elevations/Depths
Those BFEs and base flood depths determined through analyses in which the methodologies used have not been applied properly, are based on insufficient or poor-quality data, or do not account for the effects of physical changes that have occurred in the floodplain. <p><a href="#top">Back to top</a></p>
Temporary Bench Mark (TBM)
Benchmark established for a particular mapping project or community. <p><a href="#top">Back to top</a></p>
Terrestrial Species
<p>Types of species of animals and plants that live on or grow from the land.</p> <p><a href="#top">Back to top</a></p>
Third Party Impacts
The occurrence of incidental economic impacts to parties not directly related to (impactcausing) water management actions. For example, agricultural land retirement can impact local tax revenues and/or labor conditions, etc. <p><a href="#top">Back to top</a></p>
Through-Delta Conveyance
<p>A means of improving conveyance across the Delta by a variety of modifications to Delta channels.</p> <p><a href="#top">Back to top</a></p>
Tieback Levees
Levees that extend from the main levees along a river, lake, or coast to bluff line (high ground) and are part of the lines-of-protection. <p><a href="#top">Back to top</a></p>
Tile Water (Tile Drainage)
The water drained from agricultural fields by the practice of removing excess water from the subsurface of soil with a network of below-ground pipes that allow subsurface water to move out from between soil particles and into the tile line. Water flowing through tile lines is often ultimately deposited into surface water. Water enters the tile line either via the gaps between tile sections, in the case of older tile designs, or through small perforations in modern plastic tile. Tile drainage brings soil moisture levels down for optimal crop growth and is used as a primary method of controlling soil salinity. <p><a href="#top">Back to top</a></p>
Total Capital Cost
Total monetary cost of option required for ÒturnkeyÓ implementation including environmental and third party impact mitigation, storage, conveyance, energy, capitalized operations and maintenance, administrative, planning, legal and engineering costs. <p><a href="#top">Back to top</a></p>
Total Commercial Activity
The amount of commercial activity (e.g., employment, productivity, commercial land use) that occurs in a given study area. This factor is a driver of (and indicator for) commercial water use and includes institutional water use (government offices, schools, etc.) as well. See also commercial activity mix. <p><a href="#top">Back to top</a></p>
Total Desalination
Water coming from any source that is desalted by reverse osmosis or other processes. See also desalination. <p><a href="#top">Back to top</a></p>
Total Groundwater Natural Recharge
The percolation to groundwater basins from precipitation falling on the land and from flows in rivers and streams. <p><a href="#top">Back to top</a></p>
Total Industrial Activity
The total amount of industrial activity (e.g., employment, productivity, industrial land use, etc) that occurs in a given study area. This factor is a driver of (and indicator for) industrial water use. <p><a href="#top">Back to top</a></p>
Total Irrigated Crop Area
The total area of irrigated crops (by type) planted in a planning area during a given year. This number includes multiple cropping. <p><a href="#top">Back to top</a></p>
Total Maximum Daily Load
TMDL is a calculation of the maximum amount of a pollutant that at water body can receive and still safely meet water quality standards. <p><a href="#top">Back to top</a></p>
Total Population
The statewide total population projection regardless of geographical distribution. Context: Scenario Factor. <p><a href="#top">Back to top</a></p>
Tracy Pumping Plant
<p>The CVP export pumping plant in the south Delta.</p> <p><a href="#top">Back to top</a></p>
Transient Noncommunity Water System
Serves 25 or more people for at least 60 days per year. (cf. nontransient noncommunity water system) <p><a href="#top">Back to top</a></p>
An essential physiological process in which plant tissues give off water vapor to the atmosphere. <p><a href="#top">Back to top</a></p>
Triangulated Irregular Network (TIN)
A set of non-overlapping triangles developed from irregularly spaced points that are used to represent the facets of a surface. <p><a href="#top">Back to top</a></p>
Twitchell Island
UC Davis
Unaccounted for Water
Deteriorated and aging infrastructure can play an important role in unaccounted for water (sometimes referred to as water losses), contributing to significant water leakage and a high rate of main breaks. Water utilities are conducting audits to identify water main leaks, unmetered water use for parks and recreation consumption, water theft and inaccurate meters. <p><a href="#top">Back to top</a></p>
Unconfined Aquifer
An aquifer which is not bounded on top by an aquitard. The upper surface of an unconfined aquifer is the water table. See also artesian aquifer. (cf. confined aquifer and semi-confined aquifer) <p><a href="#top">Back to top</a></p>
Underground Stream
Body of water flowing as a definite current in a distinct channel below the surface of the ground, usually in an area characterized by joints or fissures. <p><a href="#top">Back to top</a></p>
The upward pressure on the land behind a levee system that is exerted by groundwater, under pressure from the flooding source, when the elevation of the floodwaters are higher than the elevation of the land. <p><a href="#top">Back to top</a></p>
Unit Applied Water
The quantity of water applied to a specific crop per unit area (sometimes expressed in inches of depth). <p><a href="#top">Back to top</a></p>
Unnumbered A Zones
Flood insurance risk zones, designated ÒZone AÓ on an FHBM, FIRM, or DFIRM, that are based on approximate studies. <p><a href="#top">Back to top</a></p>
Unsaturated Zone
The zone below the land surface in which pore space contains both water and air. <p><a href="#top">Back to top</a></p>
Upstream Storage
<p>Any water storage upstream of the Delta supplied by the Sacramento or San Joaquin Rivers or their tributaries.</p> <p><a href="#top">Back to top</a></p>
Urban Commercial Use
The water used by light industry and light or non-manufacturing business establishments including retail services, office buildings, restaurants, dry cleaners, and other consumer-oriented services or businesses. Also includes employee uses and recreational facilities (temporary lodging). This can include institutional or governmental use as well. <p><a href="#top">Back to top</a></p>
Urban Energy Production
The water used for refineries and cooling in thermoelectric power generation. <p><a href="#top">Back to top</a></p>
Urban Industrial Use
The heavy water using manufacturing with cooling towersÑfor processing, manufacturing, and other industrial plant uses (canneries, mills or other large complex users of supply) as defined by the North American Industry Classification System (NAICS). This water can be used as cooling water, or for rinsing, washing, diluting, and other sanitation operations. Also included are employee uses and landscape irrigation. <p><a href="#top">Back to top</a></p>
Urban land Use Management
Planning for the housing and economic development needs of the growing population while providing for the efficient use of water and other resources. <p><a href="#top">Back to top</a></p>
Urban Large Landscape
The water used to irrigate recreational and large landscape areas such as golf courses, parks, play fields, highway medians, and cemeteries. <p><a href="#top">Back to top</a></p>
Urban Residential Use-Single
Interior: The water used within a single-family, detached housing unit for such uses as personal hygiene, cooking, drinking, and laundry. Exterior: The water used outside of a single family, detached housing unit. Uses include landscape irrigation, swimming pools, car washing, sidewalk cleaning, and the watering of domestic animals. <p><a href="#top">Back to top</a></p>
Urban Runoff Management
A broad series of activities to manage both storm water and dry weather runoff. <p><a href="#top">Back to top</a></p>
Urban Wastewater Produced
Flow from urban areas into urban wastewater treatment plants. <p><a href="#top">Back to top</a></p>
Urban Water Management Planning Act
Sections 10610 through 10657 of the California Water Code. The Act requires urban water suppliers to prepare urban water management plans which describe and evaluate sources of water supplies, efficient uses of water, demand management measures, implementation strategies and schedules, and other relevant information and programs within their water service areas. Urban water suppliers (CWC Section 10617) are either publicly or privately owned and provide water for municipal purposes, either directly or indirectly, to more than 3,000 customers or supply more than 3,000 acre-feet of water annually. <p><a href="#top">Back to top</a></p>
Urban Water Reliability (average)
<p>A measure of a systemÕs ability to sustain the social, environmental, and economic systems that it serves during a year of average participation. Context: Evaluation Criteria</p> <p><a href="#top">Back to top</a></p>
Urban Water Reliability (dry)
<p>A measure of a systemÕs ability to sustain the social, environmental, and economic systems that it serves during a dry year. Context: Evaluation Criteria</p> <p><a href="#top">Back to top</a></p>
Urban Water Reliability (wet)
<p>A measure of a systemÕs ability to sustain the social, environmental and economic systems that it serves during a wet year. Context: Evaluation Criteria</p> <p><a href="#top">Back to top</a></p>
Urban Water Use
The use of potable and non-potable water for urban purposes including, but not limited to, residential, commercial, industrial, recreation, energy production, military, and institutional classes. These are types of uses rather than places of use. <p><a href="#top">Back to top</a></p>
Urban Water Use Efficiency
<p>Methods or technologies resulting in the same beneficial residential, commercial, industrial, and institutional uses with less water or increased beneficial uses from existing water quantities.</p> <p><a href="#top">Back to top</a></p>
Usable Storage Capacity
The quantity of groundwater of acceptable quality that can be economically withdrawn from storage. <p><a href="#top">Back to top</a></p>
USACE Levees
Levees that are within the programs operated by the U.S, Army Corps of Engineers, including levees that were built by the USACE that were authorized for construction by the U.S. Congress or by USACE continuing authorities (e.g., Section 205); levee projects constructed by non-Federal interests or other (non-USACE) Federal agencies and incorporated into the USACE Federal system by specific congressional action; Federal projects that are either operated and maintained by the USACE or turned over to a local sponsor for operation and maintenance; and Non-Federal projects within the Rehabilitation and Inspection Program (RIP), Public Law 84-99). <p><a href="#top">Back to top</a></p>
Use Values
vs. non-use values (direct, indirect, option, and bequest vs. Ôbecause it existsÕ). Context: ecosystem valuation methods. <p><a href="#top">Back to top</a></p>
Variable Fluoridation
Fluoridation at levels up to optimal level depending on many factors, including time of year, water demand, and the use of sources that may not have fluoridation treatment facilities. Variable fluoridation is most often the result of a water system receiving fluoridated water from a wholesale provider, while also using local unflouridated water sources. <p><a href="#top">Back to top</a></p>
Velocity Zone
See Coastal High Hazard Area. <p><a href="#top">Back to top</a></p>
Vernal Pools
Subset of wetlands that occur in shallow foothill and valley depressions. Water usually remains in the pools and swales from only a few days to a few months. The presence of low permeability soils (e.g., clay, hardpan) generally limit water filtration. <p><a href="#top">Back to top</a></p>
The vision statement describes the desired future for California water resources and management and serves as a foundation for water and flood planning during the planning horizon. <p><a href="#top">Back to top</a></p>
Volatile Organic Compound (VOC)
A human-made organic compound that readily vaporizes in the atmosphere. These compounds are often highly mobile in the groundwater system and are generally associated with industrial activities. <p><a href="#top">Back to top</a></p>
Waiting Period
The time between the date of application and the policy effective date. <p><a href="#top">Back to top</a></p>
Wastewater Reclamation
ÒWater reclamationÓ or Òwastewater reclamationÓ can have two meanings: (1) the process of treating wastewater for beneficial use, storing and distributing recycled water, and (2) the actual use of recycled water. This definition is the more common meaning, depending on the context: The treatment of water of impaired quality to produce a water of suitable quality for intended use. See also water recycling, water reuse. <p><a href="#top">Back to top</a></p>
Water Bag Transport/Storage Technology
<p>Water diverted in areas that have unallocated fresh water supplies, storing the water in large inflatable bladders, and towing to an alternate coastal region.</p> <p><a href="#top">Back to top</a></p>
Water Conservation
<p>Those practices that encourage consumers to reduce the use of water. The extent to which these practices actually create a savings in water depends on the total or basin-wide use of water.</p> <p><a href="#top">Back to top</a></p>
Water Demand
The desired quantity of water that would be used if the water is available and a number of other factors such as price do not change. Demand is not static. <p><a href="#top">Back to top</a></p>
Water Demand Elasticity
The desire to use water is based on a number of factors such as the intended use for the water, the price of water, and the cost of alternative ways to meet the intended use. <p><a href="#top">Back to top</a></p>
Water Depletion
Net water use minus water that can be later recovered, such as deep percolation and return flow, to developed supply. <p><a href="#top">Back to top</a></p>
Water Exchanges
Typically water delivered by one water user to another water user; the receiving water user will return the water at a specified time or when the conditions of the parties\ agreement are met. (See also water transfers.) <p><a href="#top">Back to top</a></p>
Water from Refineries
Water produced as a byproduct of the oil or gas refining process. <p><a href="#top">Back to top</a></p>
Water in the Environment
Consumptive and nonconsumptive use of water, not including agricultural and urban uses. Defined by the Sustainability Roundtable as Òa measure of the water remaining in the environment after withdrawals and consumption.Ó <p><a href="#top">Back to top</a></p>
Water PIE
In May 2008, DWR launched a working prototype of the Water Planning Information Exchange (Water PIE), an online information exchange system to share water management information between State, regional and local agencies and government. See Integrated Water Resources Information System (IWRIS). <p><a href="#top">Back to top</a></p>
Water Portfolio
A picture of the water supply and use for a given year statewide or by region, subject to availability of data; includes the flow diagram, flow diagram table, water balances, and summary table. <p><a href="#top">Back to top</a></p>
Water Quality
Water quality
Water Quality
Water Quality
Description of the chemical, physical, and biological characteristics of water, usually in regard to its suitability for a particular purpose or use. <p><a href="#top">Back to top</a></p>
Water Reclamation
<p>Practices that treat and reuse water. The waste water is treated to meet health and safety standards depending on its intended use. Also called water recycling.</p> <p><a href="#top">Back to top</a></p>
Water Recycling
Two meanings: (1) see the first definition of water reclamation above, which currently is the most common usage; (2) the reuse or recirculation of water through the same series of processes, pipes, or vessels more than once by one user, often without treatment between uses, such as in cooling towers or cascading uses within an industry where the wastewater from one process is the source water for another process. See wastewater reclamation, water reuse. <p><a href="#top">Back to top</a></p>
Water Reliability
(dry) A measure of a systemÕs ability to sustain the social, environmental, and economic systems that it serves during a dry year. (Wet) A measure of a systemÕs ability to sustain the social, environmental, and economic systems which it serves during a wet year. <p><a href="#top">Back to top</a></p>
Water Reuse
The additional use of previously used water, with or without treatment. This term also often takes on the more encompassing meaning in the first definition of Òwater reclamationÓ above. ÒDirect reuseÓ is the use of recycled water that has been transported from a wastewater treatment plant to a reuse site without passing through a natural body of either surface or groundwater. This is also called Òpipe-to-pipeÓ reuse where the recycled water is conveyed in a distribution system after treatment. ÒIndirect reuseÓ is the use of recycled water indirectly after it has passed through a natural body of water after discharge from a wastewater treatment plant. Groundwater recharge is an example. Another is the reuse of Sacramento\s wastewater after discharge by downstream users. ÒPlanned reuseÓ is the deliberate direct or indirect use of recycled water without relinquishing control over the water during its delivery. Direct reuse is always considered planned because it involves delivery in a distribution system leading from the wastewater treatment plant to the point of reuse. ÒUnplanned reuseÓ or Òincidental reuseÓ is the unplanned use of wastewater after disposal. The reuse of Sacramento\s effluent by downstream users is considered unplanned; there is no planned intent by Sacramento to have the State Water Project pump a portion the effluent to Southern California. See water reclamation. <p><a href="#top">Back to top</a></p>
Water Rights
In water law, refers to the right of a user to use water from a water source, e.g., a river, stream, pond or source of groundwater. <p><a href="#top">Back to top</a></p>
Water Service Area
Geographic area in which a water agency is the designated water service provider. <p><a href="#top">Back to top</a></p>
Water Supply
Water Supply Exports
The amount of water that a region transfers to another to meet needs. <p><a href="#top">Back to top</a></p>
Water Supply Imports
The amount of water that brought in from other regions to meet needs. See water transfer. <p><a href="#top">Back to top</a></p>
Water table
See groundwater table. <p><a href="#top">Back to top</a></p>
Water Transfer
A water transfer is defined in the Water Code1 as a temporary or long-term change in the point of diversion, place of use, or purpose of use due to a transfer or exchange of water or water rights. Many transfers, such as those among contractors of the State Water Project or Central Valley Project, do not fit this definition. A more general definition is that water transfers are a voluntary change in the way water is usually distributed among water users in response to water scarcity. Compare to water exchanges, which are typically water delivered by one water user to another water user; the receiving water user will return the water at a specified time or when the conditions of the parties to the agreement are met. <p><a href="#top">Back to top</a></p>
Water Transfers
<p>Voluntary water transactions conducted under state law and in keeping with federal regulations.</p> <p><a href="#top">Back to top</a></p>
Water Transfers-Regional
<p>Water that is transferred within a hydrologic region from one agency to another. Transfer requires approval from the State Water Resources Control Board for a change in place of use. Imported Ð Water that is transferred across hydrologic region boundaries from one agency to another. Transfer requires approval from the State Water Resources Control Board for a change in place of use.</p> <p><a href="#top">Back to top</a></p>
Water treatment
Active water treatment consists of any method where energy is necessary to process the effluent. Passive water treatment includes the use of settling ponds, wetlands and field rotation in pastures <p><a href="#top">Back to top</a></p>
Water year
A continuous 12-month period for which hydrologic records are compiled and summarized. Different agencies may use different calendar periods for their water years. DWR water year is Oct 1 through Sep 30. <p><a href="#top">Back to top</a></p>
Water-Surface Elevations (WSELs)
The heights of floods of various magnitudes and frequencies in the floodplains of coastal or riverine areas, in relation to a specified vertical datum. <p><a href="#top">Back to top</a></p>
<p>An area that drains to a particular channel or river, usually bounded peripherally by a natural divide of some kind such as a hill, ridge, or mountain.</p> <p><a href="#top">Back to top</a></p>
Watershed Management
The process of evaluating, planning, managing, restoring, and organizing land and other resource use within an area that has a single common drainage point. <p><a href="#top">Back to top</a></p>
Watershed Management Area
WMAs are geographically defined watershed areas where the Regional Water Boards will implement the watershed approach. See Watershed Management Initiative. <p><a href="#top">Back to top</a></p>
Watershed Management Initiative
The WMI remains a part of the State Water Boards Strategic Plan. The WMI establishes a broad framework overlying the numerous federal- and State-mandated priorities. As such, the WMI helps the Water Boards achieve water resource protection, enhancement and restoration while balancing economic and environmental impacts. See also watershed management areas. <p><a href="#top">Back to top</a></p>
Wave Height
The vertical distance between the wave crest and the wave trough. <p><a href="#top">Back to top</a></p>
Wave Height Adjustment
A measurement that is added to the base flood elevation for V Zones shown on the Flood Insurance Rate Map published prior to 1981. For coastal communities, the base flood elevation shown on Flood Insurance Rate Maps published prior to 1981 are still-water elevations, which include only the effects of tide and storm surge, and not the height of wind-generated waves. <p><a href="#top">Back to top</a></p>
Wave Runup
The rush of wave water up a slope or structure. <p><a href="#top">Back to top</a></p>
Wave Setup
The increase in the still water surface near the shoreline, due to the presence of breaking waves. <p><a href="#top">Back to top</a></p>
Wet season
The period of time on an annual cycle in which the majority of rainfall occurs. <p><a href="#top">Back to top</a></p>
What we do
White Paper
White Paper
White Papers
Read public comments received on the White Papers
Why we do it
Wild and Scenic River
State- and federal-designated river system; 17 rivers in California including many forks and tributaries, about 1,900 miles of river are designed wild, scenic, or recreational. Authority: 1968 National Wild and Scenic Rivers Act and the California Wild and Scenic Rivers Act of 1972. <p><a href="#top">Back to top</a></p>
Wild and Scenic Rivers Net Water Use
Annual natural flows from the designated State and federal Wild and Scenic Rivers system. <p><a href="#top">Back to top</a></p>
Willingness to Accept
A comparable concept to willingness to pay is called willingness to accept or willingness to receive, which measures how much an individual who is a seller would accept or receive as payment if he or she could be induced to forgo a good or service. The amount of payment can then be equated to the economic value of the good or service. In short, the economic value to a seller is equal to his or her Òwillingness to accept.Ó Context: Ecosystem Valuation Methods. <p><a href="#top">Back to top</a></p>
Willingness to Pay
(1)The economic value of a good or service to a person who is a buyer is measured by the maximum amount of other things that he or she is willing to give up in order to acquire that good or service cf willingness to accept. (2) Quantifiable financial support for watershed management in which individuals have a willingness to pay for services provided by a well-managed watershed. Context: (1) Ecosystem Valuation Methods, (2) Resource Management Strategy. <p><a href="#top">Back to top</a></p>
Working landscape
An economically and ecologically vital and sustainable landscape where agricultural and other natural resource-based producers generate multiple public benefits while providing for their own and their communitiesÕ economic and social well-being. Context: resources management strategy. <p><a href="#top">Back to top</a></p>
Write Your Own (WYO) Program
A cooperative undertaking of the insurance industry and FEMA begun in October 1983. The WYO Program operates within the context of the NFIP and involves private insurance carriers who issue and service NFIP policies. <p><a href="#top">Back to top</a></p>
<p>The location (measured in kilometers upstream from the Golden Gate Bridge) of 2 parts per thousand total dissolved solids. The length of time X2 must be positioned at set locations in the estuary in each month is determined by a formula that considers the previous month’s inflow to the Delta and a “Level of Development” factor, denoted by a particular year. X2 is currently used as the primary indicator in managing Delta outflows. The X2 indicator is also used to reflect a variety of biological consequences related to the magnitude of fresh water flowing downstream through the estuary and the upstream flow of salt water in the lower portion of the estuary. The outflow that determines the location of X2 also affects both the downstream transport of some<br />organisms and the upstream movement of others and affects the overall water operations of the CVP and SWP.</p> <p><a href="#top">Back to top</a></p>
A geographical area shown on a Flood Hazard Boundary Map or a Flood Insurance Rate Map that reflects the severity or type of flooding in the area. <p><a href="#top">Back to top</a></p>
Zone A99 Determination
See Adequate Progress Determination. <p><a href="#top">Back to top</a></p>
Zone AR Determination
See Flood Protection Restoration Determination. <p><a href="#top">Back to top</a></p>
Zone Gutter
Boundary, shown on a FIRM or DFIRM, dividing SFHAs of different BFEs, base flood depths, flow velocities, or flood insurance risk zone designations. <p><a href="#top">Back to top</a></p>

Coequal goals

The Delta Stewardship Council was created in legislation to achieve the state mandated coequal goals for the Delta. "'Coequal goals' means the two goals of providing a more reliable water supply for California and protecting, restoring, and enhancing the Delta ecosystem. The coequal goals shall be achieved in a manner that protects and enhances the unique cultural, recreational, natural resource, and agricultural values of the Delta as an evolving place." (CA Water Code §85054)