Patterns and magnitude of flow alteration in California, USA

Freshwater Biology (Wiley) | December 27th, 2017

The importance of the natural flow regime to stream and river health has received growing attention over the last two decades. Quantifying natural river flows has become

The importance of the natural flow regime to stream and river health has received growing attention over the last two decades. Quantifying natural river flows has become an essential component of water resource planning, including assessments of water supplies (Vicuna,Maurer, Joyce, Dracup, & Purkey, 2007; Wurbs, 2005), reservoir operations (Hejazi, Cai, & Ruddell, 2008) and drought risk (Meko,Therrell, Baisan, & Hughes, 2001). Understanding the natural flow regime is also crucial for managing stream ecosystems.

Petition for 2023 Drought Emergency Regulation or Other Emergency Action to Protect Nesting Birds, Water Quality, and other Public Trust Resources at Mono Lake

Mono Lake Committee | December 16th, 2022

Physical and Hydrologic Assessment of the Carmel River Watershed California

California State University, Monterey Bay (CSUMB) | November 1st, 2004

The Carmel Watershed is a terrestrial jewel in the California landscape. Its forested headwaters harvest rain from the Pacific storms each winter, providing a nat

The Carmel Watershed is a terrestrial jewel in the California landscape. Its forested headwaters harvest rain from the Pacific storms each winter, providing a natural cascade of resources enjoyed by human residents and the broader ecosystem. Although the Carmel River is not currently listed as “impaired” by the State of California, there have been significant human impacts that could lead to impaired waters. These impacts are now recognized and defined in this report so that remediation and future management policies can be developed. This report is one facet of the Carmel Watershed Assessment orchestrated by the Carmel River Watershed Conservancy. We assess the physical and hydrologic components of the watershed, chiefly focusing on two major classes of problems, water quantity and excess sediment. Both of these issues are important when considering human needs and the needs of the broader ecosystem, including endangered aquatic and riparian species. The Carmel Watershed has finite annual rainfall as its only water resource. That resource is currently stretched too thin, leaving new urban, suburban, rural, and industrial development in and around the watershed at odds with pre-existing water appropriation and environmental requirements (e.g., SWRCB, 1995a; 1995b). Certain kinds of common land-uses and road designs supply excess sediment above natural background rates. Some of the major problems in the watershed are summarized below, in no particular order. Demand for water far exceeds water supply, leading to many related subordinate problems, including diminished surface water for endangered steelhead trout. Extensive urbanization exists within the regulatory 100-year floodplain and in the dam-failure inundation zone. Excess sediment is generated from a very large number of dirt roads, some of which are abandoned, some of which out of compliance with grading ordinances, but most of which are clearly within regulations. Nearly all sub-road drainage culverts are undersized, leading to downstream erosion, whether related to dirt roads, paved roads, or highways. Excess sediment is generated by a great number of bare road cuts on dirt roads, paved roads, and highways. Excess sediment is generated in the Los Chupines and Sycamore Creek drainages by soil slip, gullies, unstable stream banks, and roads. Many of those issues are related to cattle impacts. Excess sediment is generated in a great number of incised streams that have tall, exposed banks. San Clemente Dam is unsafe owing to sediment burden and proximity to active faults. Decommissioning the San Clemente Dam will likely lead to a significant shift in river morphology and flood response, owing to the restoration of historic bedload transport rates. Los Padres Dam is rapidly infilling with sediment and is also close to active faults. Watershed impairment is the result of incremental, permitted, changes that have a large cumulative impact on the watershed. Closer adherence to the Carmel Valley Master Plan (CVMP, 1996; Appendix C) and County ordinances will foster resource sustainability and aesthetic living conditions. Among the salient points in that document are the following guidelines for development (CVMP, 1996). 1. Preserve the rural character of the Carmel Valley 2. Protect all natural resources with emphasis on biological communities, agricultural lands, the Carmel River and its Riparian corridor, air quality and scenic resources. We note that the large-scale negative impacts we describe in the Carmel Watershed mainly resulted from the cumulative effects of small, insignificant, permitted landscape or hydrologic alterations (e.g., Dunne et al., 2001). With that in mind, guidelines for sustainable resource use could begin with an agreed upon ultimate level of resource use, depletion, or degradation, beyond which, no further landscape or hydrologic alterations will be permitted. Using water supply as an example, the best strategy for sustainability is to determine the total cumulative resource usage, and then stop permitting further requests for resource use when the agreed upon cumulative impact is met—the concept of water rights appropriation. This same “cumulative impact” management strategy could be applied to other cumulative watershed impacts, such as total miles of dirt road per square mile of watershed area, or total area of impervious cover per square mile of watershed area. These strategies can be applied once a cumulative impact target has been established upon sound science, and codified by stakeholder agreement. Considering that the cumulative negative impacts in the watershed are the net result of innumerable, insignificant modifications, we can predict that innumerable, small positive restorative efforts in the watershed would eventually produce large positive impacts on watershed health including water quality and quantity.

Pilot Projects to Increase Colorado River System Water in Lake Powell and Lake Mead

U.S. Bureau of Reclamation (USBR) | January 14th, 2022

From calendar year 2015 through 2018, 64 projects were implemented in the Upper Basin resulting in an estimated 47,280 acre-feet of Colorado River System water conserved

From calendar year 2015 through 2018, 64 projects were implemented in the Upper Basin resulting in an estimated 47,280 acre-feet of Colorado River System water conserved in the Upper Basin at a cost of $8.5 million or $180.23 per acre-foot on average. From January 2015 through December 31, 2019 in the Lower Basin, 16 projects were implemented which will result in 175,347 acre-feet of Colorado River System water in Lake Mead by 2035, at a cost of approximately $29.8 million or $170.14 per acre-foot on average. The Pilot Program successfully demonstrated that voluntary, compensated water conservation projects can conserve water for Colorado River System storage to help mitigate the impacts of drought.

Piloting a Water Rights Information System for California

Center for Law, Energy, and the Environment (CLEE) | July 15th, 2021

California’s complex water management challenges are growing and intensifying. Systemic stressors like the more frequent and severe droughts and floods driven by climat

California’s complex water management challenges are growing and intensifying. Systemic stressors like the more frequent and severe droughts and floods driven by climate change are only making it harder to respond. Accordingly, California needs to dramatically improve the ability of local, regional, and State entities to make agile and effective water management decisions. We believe doing so will require enhanced understanding of our water resources and how they align with the needs of a range of agencies and stakeholders. Water rights data provide a crucial opportunity for advancing this understanding. We find that modernizing water rights data is feasible, affordable, and can increase transparency and clarity for better decision-making.

Pixley Irrigation District Groundwater Sustainability Plan

Pixley Irrigation District Groundwater Sustainability Agency (PIDGSA) | January 21st, 2020

Pixley Irrigation District Groundwater Sustainability Plan (Revised)

Pixley Irrigation District Groundwater Sustainability Agency (PIDGSA) | July 27th, 2022

The Tule Subbasin is designated by DWR as a critically overdrafted basin with an estimated subbasin average overdraft of 115,300 acre-feet per year. The Agencies estimat

The Tule Subbasin is designated by DWR as a critically overdrafted basin with an estimated subbasin average overdraft of 115,300 acre-feet per year. The Agencies estimated annual average overdraft within the Tule Subbasin is 70,000 acre-feet per year. The overdraft conditions have caused issues for those reliant on groundwater pumping, which include municipal, domestic, and agriculture users. Other issues generated from the overdraft include areas of land subsidence, which predominantly occur in the northwestern portion of the Agency. A sample of the Pixley GSP is displayed below. Due to size, this full 2,421-page document must be downloaded from the Department of Water Resources.

Planned operation of large-scale water-distribution system

American Society of Civil Engineers (ASCE) | May 1st, 1995

A water-supply-distribution-system planning model has been developed using a directed graph algorithm as its pre- and post-processors and a linear programming (LP) proced

A water-supply-distribution-system planning model has been developed using a directed graph algorithm as its pre- and post-processors and a linear programming (LP) procedure as an “intelligent” system operator at its core. The directed graph, as a preprocessor, is used to produce a mathematical representation of the distribution system in question, to check the consistency and correctness of the network topology before an input file is created for the LP procedure. In the postprocessing mode, the directed graph generates files for graphical displays of model results and performs graph analyses such as depth- and breadth-first traversals, cut-set and connectivity for evaluating water-quality blending, tracking of source-to-demand contributions, system reliability, and lifeline objectives. Unlike the conventional formulation of a resource-allocation problem, the demand requirements, storage capacities, and other system constraints are removed from the constraint set and translated into a composite objective function. This methodology was successfully applied to the Metropolitan Water District of Southern California's (MWD's) distribution system. The results indicate that the combination of using an LP procedure and graph algorithm is a very versatile tool for solving large-scale water-distribution problems. This paper documents the concept used in developing the system-planning model and the results of its application to a simplified example as well as application to four case studies involving the entire MWD's distribution system.

Plumbing the Depths: Californians Without Toilets and Running Water

Pacific Institute | July 15th, 2019

California’s Human Right to Water law states that “every human being has the right to safe, clean, affordable, and accessible water adequate for human consumption

California’s Human Right to Water law states that “every human being has the right to safe, clean, affordable, and accessible water adequate for human consumption, cooking, and sanitary purposes.” To date, the policy discussion on meeting California’s Human Right to Water has focused largely on expanding and improving drinking water utility services in the state, and improving the quality and reliability of drinking water for rural households using domestic wells. Sanitation and wastewater have received less attention. There also has been less attention paid to individuals and households in communities served by functional water and wastewater utilities but lacking the plumbing necessary to access those services. To partially remedy these gaps, we set out to better understand the number of Californians with inadequate access to toilets and hot and cold running water.

Policy for Water Quality Control for Recycled Water (Recycled Water Policy)

California State Water Resources Control Board (SWRCB) | June 21st, 2013

The purpose of this Policy is to increase the use of recycled water from municipal wastewater sources that meets the definition in Water Code section 13050(n), in a manne

The purpose of this Policy is to increase the use of recycled water from municipal wastewater sources that meets the definition in Water Code section 13050(n), in a manner that implements state and federal water quality laws. The State Water Board expects to develop additional policies to encourage the use of stormwater, encourage water conservation, encourage the conjunctive use of surface and groundwater, and improve the use of local water supplies. When used in compliance with this Policy, Title 22 and all applicable state and federal water quality laws, the State Water Board finds that recycled water is safe for approved uses, and strongly supports recycled water as a safe alternative to potable water for such approved uses.