HEC-HMS Models for the Sacramento and San Joaquin River Basins Comprehensive Study

U.S. Army Corps of Engineers (USACE) | August 1st, 2001

Due to several large and damaging flood events on the Sacramento and San Joaquin Rivers (California) during the 1980s and 1990s, the U.S. House of Representatives

Due to several large and damaging flood events on the Sacramento and San Joaquin Rivers (California) during the 1980s and 1990s, the U.S. House of Representatives directed the Sacramento District to develop comprehensive plans for flood control for the two rivers and to develop hydrologic and hydraulic models of the river systems. The models will be used to provide better forecasts and evaluations of flood damage reduction alternatives. Additionally, the model results will be used as input for reservoir simulation models. The Sacramento River Basin and the San Joaquin River/Tulare Lake Bed Basins comprise nearly 60,000 square miles, drain California’s Central Valley floor and receive much of their runoff from the Sierra Nevada mountain range. Developing hydrologic models for the tributary basins (which included extremely variable terrain) within a ten month time period was a formidable task. The District contacted the Hydrologic Engineering Center (HEC) to assist with the development of these models. HEC used the Hydrologic Modeling System program, HEC-HMS, and introduced the HEC-GeoHMS grid-based technology to perform the hydrologic study. GeoHMS is an ArcView® extension that provides automated subbasin delineation methods and calculates many physical characteristics used for estimation of hydrologic parameters. HEC developed and calibrated 33 individual HEC-HMS models for the major tributaries and portions of the valley floors of the Sacramento River Basin and the San Joaquin River / Tulare Lake Bed Basins. GeoHMS was used to delineate the individual river basins, perform initial subbasin delineation and develop the physical characteristics for the subbasins. Tools within GeoHMS allowed the modelers to iteratively redelineate their subbasins, as appropriate, to meet project needs. Keeping the modeling effort consistent was critical to the success of the study. To ensure this consistency of procedures and results, HEC developed modeling guidelines that each of the 11 modeling teams followed. Once the grid-based HEC-HMS models were developed, HEC contracted with the Corps’ Cold Regions Research and Engineering Laboratory (CRREL) to perform a snowmelt study for the watersheds. HEC provided a gridded precipitation file (4 km2) to CRREL. Through the use of their Distributed Snow Process Model (DSPM), CRREL then provided a gridded snowmelt/ precipitation file to HEC. DSPM computes snowmelt and rainfall depths at the soil surface on a grid-cell basis. This data is used directly by HEC-HMS as precipitation on the watershed. The ModClark rainfall to runoff transformation was used to compute the subbasin hydrographs. HEC-HMS parameter optimization models were developed at hourly flow gages for the unregulated headwater streams. The runoff parameter optimization models allowed the modelers to develop the runoff parameters necessary for the regression analysis. A number of physical characteristics were evaluated for correlation with variations in Clark’s time of concentration, TC, for the optimization models. The results of the regression analysis allowed the modelers to populate the ungaged subbasins with appropriate unit hydrograph parameters. Approximately 200 hourly flow gages and 83 reservoirs were considered in calibrating the models. The 33 individual basin models were then given to the Sacramento District.

Historical Expenditures and Current and Future Funding Needs

California Department of Water Resources (DWR) | December 13th, 2018

This document supports information contained in the California Water Plan Update 2018. The purpose of this document is to provide a description of California’s water re

This document supports information contained in the California Water Plan Update 2018. The purpose of this document is to provide a description of California’s water resources management historical expenditures and the existing funding needs in the State. The historical expenditure data includes capital and ongoing public agencies’ (State, local, and Federal agencies) historical expenditures. Historical expenditure data is organized by management action type and water sectors. In this document, capital management actions include infrastructure development, repair, replacement or rehabilitation. Ongoing actions include planning, data management, tracking and reporting, operations, and maintenance. Historical expenditure data is provided for State fiscal year 2005/2006 (2006) to 2014/2015 (2015). This timeframe was selected due to data availability at the local, State, and Federal levels. This document also provides information on the accrued interest on debt from State general obligation (GO) bonds.  This document provides information pertaining to the projected existing water management funding needs and existing water management funding gap. Projected water management funding need was estimated from planned and proposed management actions collected from State, local, and Federal agencies.  Historical expenditure and funding need information is used in the California Water Plan Update 2018 to provide context and data for inclusion into the funding analysis, described in the Funding Scenario Analysis supporting document. 

Human Use of Restored and Naturalized Delta Landscapes

University of California, Davis (UC Davis) | October 31st, 2016

Current legislation and state plans for the California Delta call for large-scale restoration of aquatic and terrestrial habitats, which will require significant changes

Current legislation and state plans for the California Delta call for large-scale restoration of aquatic and terrestrial habitats, which will require significant changes in land uses and cultural patterns to achieve. Yet landscapes that are restored for habitat for other-than human species will remain subject to human uses. This report looks at how human presence can and will continue after restoration, and considers how these uses can be best reconciled with cultural, ecological and adaptive management goals. Our one year study builds off other research projects that have explored the California Delta from an integrative human-environment perspective. It uses a landscape planning approach that attempts to push beyond single sectoral methods, seeking a holistic integration of multiple goals and land use agendas spanning across ecological, social, economic and political domains. This report’s findings are based on surveys, interviews, review of existing Delta planning literature, field work and specific landscape case studies. In general, our research supports the advancement of a reconciliation approach, which seeks synergies between ecosystem needs and the desires of those who live, work and play in the Delta, both now and in the future.

Hydroclimate Report Water Year 2022

California Department of Water Resources (DWR) | October 1st, 2024

Hydroclimatic Extremes as Challenges for the Water Management Community: Lessons from Oroville Dam and Hurricane Harvey

American Meteorological Society (AMS) | December 31st, 2018

Record-breaking extreme storms were a hallmark of 2017 in the United States. An extremely wet winter on the West Coast and brutally damaging hurricane season in

Record-breaking extreme storms were a hallmark of 2017 in the United States. An extremely wet winter on the West Coast and brutally damaging hurricane season in the U.S. Southeast and the Caribbean challenged communities and power-, water- and flood-management systems in ways that raised climate change concerns. Among the most severe were two periods of heavy precipitation and high runoff that exposed dangerous weaknesses in water management infrastructure and land use practices in California and Texas. In California, a record-breaking string of atmospheric river landfalls and remarkably wet winter conditions came close to causing a catastrophic failure of the emergency spillway at Oroville Dam (France et al. 2018; Abbott 2018; White et al. 2019) and less publicized concerns elsewhere (Holland et al. 2018; CNRFC 2017). In Texas, near record-doubling rainfall accumulations from Hurricane Harvey led to massive flooding (Blake and Zelinsky 2018) and dam safety challenges in Houston (Wax-Thibodeaux et al. 2017). We use these events as examples to ground the concept that attribution studies, with careful management-focused framing, can help water management better navigate such unprecedented extremes. *Chapter from the American Meteorological Society's Explaining Extreme Events of 2017 from a Climate Perspective.

Hydrodynamic Model Development Report: Sacramento-San Joaquin River Delta and Suisun Bay (Water Year 2016)

San Francisco Estuary Institute (SFEI) | December 13th, 2019

This report describes work related to hydrodynamic model development for the San Francisco Bay-Delta Estuary, undertaken as part of a broader eort to develop and apply co

This report describes work related to hydrodynamic model development for the San Francisco Bay-Delta Estuary, undertaken as part of a broader eort to develop and apply coupled biogeochemical-hydrodynamic models to inform nutrient management decisions. The primary intended application of the hydrodynamic model output is for use as input to an offline coupled biogeochemical model to simulate a wide range of state variables and processes, including: advective and dispersive transport, nutrient transformations, phytoplankton production, benthic and pelagic grazing, sediment diagenesis, and oxygen cycling.

Hydrogeology and Water Supply of Salinas Valley

Monterey County Water Resources Agency (MCWRA) | June 15th, 1995

The Monterey County Water Resources Agency (MCWRA) convened a panel of 10 geologists, hydrogeologists, and engineers familiar with Salinas Valley ground water basin to at

The Monterey County Water Resources Agency (MCWRA) convened a panel of 10 geologists, hydrogeologists, and engineers familiar with Salinas Valley ground water basin to attempt to reach agreement on the basic physical characteristics of the basin, and the surface and ground water flow within the basin. Agreement on the completeness and accuracy of existing data and previous hydrogeological studies was seen as an important first step in identifying and implementing a technically sound solution acceptable to the public that would stop seawater intrusion that began some 60 years ago. Mike Armstrong, General Manager of MCWRA, instructed the panel to review and, if possible, reach consensus on the hydrogeological characteristics of the basin, define clearly the water resources problems in the basin, and determine surface water and ground water flow within the basin. We were not requested to discuss specific local projects or political and institutional aspects of the problems. The panel met in a closed-door session in Monterey on May 24 and 25, 1995. The session was closed to the public and the press to enable the panelists to discuss and explore ideas and opinions freely without worrying about statements, questions, and hypotheses being repeated out of context. Members of the panel believe the process worked very well. This report presents our findings, conclusions, and recommendations. We were able to achieve more than our original scope of work. There was remarkable unanimity of opinion on our understanding of the physical characteristics of the basin, the hydrologic system, the interaction between surface water and ground water, and definition of the specific ground water problems in the basin. In summary, the facts we agreed upon point so compellingly toward an already identified regional solution to the Valley's ground water resources problems that the panel has included a potential solution. We have included a strong recommendation in this White Paper for implementing that regional solution.

Hydrogeology, Hydrologic Effects of Development, and Simulation of Groundwater Flow in the Borrego Valley, San Diego County, California

U.S. Geological Survey (USGS) | November 24th, 2015

The Borrego Valley is a small valley (110 square miles) in the northeastern part of San Diego County, California. Although the valley is about 60 miles northeast of city

The Borrego Valley is a small valley (110 square miles) in the northeastern part of San Diego County, California. Although the valley is about 60 miles northeast of city of San Diego, it is separated from the Pacific Ocean coast by the mountains to the west and is mostly within the boundaries of Anza-Borrego Desert State Park. From the time the basin was first settled, groundwater has been the only source of water to the valley. Groundwater is used for agricultural, recreational, and municipal purposes. Over time, groundwater withdrawal through pumping has exceeded the amount of water that has been replenished, causing groundwater-level declines of more than 100 feet in some parts of the basin. Continued pumping has resulted in an increase in pumping lifts, reduced well efficiency, dry wells, changes in water quality, and loss of natural groundwater discharge. As a result, the U.S. Geological Survey began a cooperative study of the Borrego Valley with the Borrego Water District (BWD) in 2009. The purpose of the study was to develop a greater understanding of the hydrogeology of the Borrego Valley Groundwater Basin (BVGB) and to provide tools to help evaluate the potential hydrologic effects of future development. The objectives of the study were to (1) improve the understanding of groundwater conditions and land subsidence, (2) incorporate this improved understanding into a model that would assist in the management of the groundwater resources in the Borrego Valley, and (3) use this model to test several management scenarios. This model provides the capability for the BWD and regional stakeholders to quantify the relative benefits of various options for increasing groundwater storage. The study focuses on the period 1945–2010, with scenarios 50 years into the future.

Hydrologic and Geochemical Characterization of the Santa Rosa Plain Watershed, Sonoma County, California

U.S. Geological Survey (USGS) | July 9th, 2013

The Santa Rosa Plain is home to approximately half of the population of Sonoma County, California, and faces growth in population and demand for water. Water managers are

The Santa Rosa Plain is home to approximately half of the population of Sonoma County, California, and faces growth in population and demand for water. Water managers are confronted with the challenge of meeting the increasing water demand with a combination of water sources, including local groundwater, whose future availability could be uncertain. To meet this challenge, water managers are seeking to acquire the knowledge and tools needed to understand the likely effects of future groundwater development in the Santa Rosa Plain and to identify efficient strategies for surface- and groundwater management that will ensure the long-term viability of the water supply. The U.S. Geological Survey, in cooperation with the Sonoma County Water Agency and other stakeholders in the area (cities of Cotati, Rohnert Park, Santa Rosa, and Sebastopol, town of Windsor, Cal-American Water Company, and the County of Sonoma), undertook this study to characterize the hydrology of the Santa Rosa Plain and to develop tools to better understand and manage the groundwater system. The objectives of the study are: (1) to develop an updated assessment of the hydrogeology and geochemistry of the Santa Rosa Plain; (2) to develop a fully coupled surface-water and groundwater-flow model for the Santa Rosa Plain watershed; and (3) to evaluate the potential hydrologic effects of alternative groundwater-management strategies for the basin. The purpose of this report is to describe the surface-water and groundwater hydrology, hydrogeology, and water-quality characteristics of the Santa Rosa Plain watershed and to develop a conceptual model of the hydrologic system in support of the first objective. The results from completing the second and third objectives will be described in a separate report.

Hydrological Intensification Will Increase the Complexity of Water Resource Management

American Geophysical Union (AGU) | March 9th, 2022

Climate change is intensifying the hydrologic cycle, resulting in an increase in floods and droughts. These changes increase the complexity of water resource management t

Climate change is intensifying the hydrologic cycle, resulting in an increase in floods and droughts. These changes increase the complexity of water resource management that must balance between releasing water to reduce flood risk and storing water for long periods without precipitation. Using updated climate model projections, we show that the amount of precipitation during events will become larger combined with longer dry periods where the daily evaporative demand exceeds precipitation for much of the Earth's surface. Additionally, for the late 21st century, a large portion of the years will be hydrologically intense in major river basins, resulting in conditions that deviate from those for which infrastructure and management policies were developed.