Sacramento River

Interactions between snow cover and evaporation lead to higher sensitivity of streamflow to temperature

Nature Portfolio (Springer Nature) | December 4th, 2020

Estimates of potential evaporation often neglect the effects of snow cover on evaporation process. Here, we present a definition of potential evaporation that explicitly

Estimates of potential evaporation often neglect the effects of snow cover on evaporation process. Here, we present a definition of potential evaporation that explicitly accounts for landscapes that are partially covered by snow. We show that, in the presence of snowpack, our evaporation estimates differ from conventional methods that assume evaporation from a free water surface. Specifically, we find that conventional methods overestimate potential evaporation as well as aridity, taken as the ratio of atmospheric water demand to supply, in landscapes where snowfall is significant. With dwindling snow-cover, actual aridity increases, which could explain the reduction in streamflow with decreasing snowfall. We suggest that streamflow, and hence water availability, is more sensitive to temperature changes in colder than in warmer regions.

Interagency Ecological Program Science Strategy: Needs for near-term science in five areas of emphasis

Interagency Ecological Program (IEP) | March 4th, 2016

The mission of the Interagency Ecological Program (IEP) is to provide and integrate relevant and timely ecological information for management of the Bay-Delta ecosystem a

The mission of the Interagency Ecological Program (IEP) is to provide and integrate relevant and timely ecological information for management of the Bay-Delta ecosystem and the water that flows through it. This is accomplished through collaborative and scientifically sound monitoring, research, modeling, and synthesis efforts for various aspects of the aquatic ecosystem. Building on the IEP Strategic Plan, which identifies the long-term goals and strategies to be implemented by the IEP to achieve its mission, the IEP Science Strategy provides direction to interagency science used to inform the management and ecological interests of IEP agencies in the near-term, and is one of a number of inputs used to shape the IEP Annual Work Plans. While the IEP Strategic Plan states that the Science Strategy be drafted for a 3-5 year horizon, a shorter 2-year timeframe for this first IEP Science Strategy has been adopted to allow for a more flexible internal development and review process, as well as feedback from the Bay-Delta research and stakeholder community.

Interagency Ecological Program’s Ability to Provide Science Supporting Management of the Delta

Delta Stewardship Council (Delta Council) | November 15th, 2019

Interagency Fish Passage Steering Committee 2014 Annual Report Focusing on the Shasta Dam Fish Passage Evaluation

Delta Stewardship Council (Delta Council) | July 1st, 2014

Interbasin water transfers in the United States and Canada

Nature Portfolio (Springer Nature) | January 13th, 2023

Interbasin water transfers (IBTs) can have a significant impact on the environment, water availability, and economies within the basins importing and exporting water, as

Interbasin water transfers (IBTs) can have a significant impact on the environment, water availability, and economies within the basins importing and exporting water, as well as basins downstream of these water transfers. The lack of comprehensive data identifying and describing IBTs inhibits understanding of the role IBTs play in supplying water for society, as well as their collective hydrologic impact. We develop three connected datasets inventorying IBTs in the United States and Canada, including their features, geospatial details, and water transfer volumes. We surveyed the academic and gray literature, as well as local, state, and federal water agencies, to collect, process, and verify IBTs in Canada and the United States. Our comprehensive IBT datasets represent all known transfers of untreated water that cross subregion (US) or subdrainage area (CA) boundaries, characterizing a total of 641 IBT projects. The infrastructure-level data made available by these data products can be used to close water budgets, connect water supplies to water use, and better represent human impacts within hydrologic and ecosystem models.

Interpreting Water Supply Forecasts

U.S. Bureau of Reclamation (USBR) | January 24th, 2012

For each Central Valley Project (CVP) allocation announcement, two forecasts are issued for each contract type by location within the CVP. Unless otherwise specified, all

For each Central Valley Project (CVP) allocation announcement, two forecasts are issued for each contract type by location within the CVP. Unless otherwise specified, all runoff forecasts are based on runoff volumes that would occur naturally without any upstream influences. For the February through May period, the runoff volume estimates are based on the observed inflow to date and current snow pack measurements made at the end of each preceding month. Water users need to know what the different forecasts represent if they are to use the information appropriately when making operational decisions. Following are explanations of each of the forecasts.

Introducing Time-Limited Permits to California’s Riparianism

University of California, Davis (UC Davis) | December 1st, 2023

Inventory of Recreation Facilities in the Sacramento-San Joaquin Delta (2015)

Delta Protection Commission (DPC) | February 21st, 2017

The Delta Protection Commission (Commission) is committed to national recognition of the Delta as a diverse, accessible, modern recreation and tourism destination. The Co

The Delta Protection Commission (Commission) is committed to national recognition of the Delta as a diverse, accessible, modern recreation and tourism destination. The Commission has compiled the 2015 Inventory of Recreation Facilities in the Sacramento-San Joaquin Delta which represents the current recreation resources in the Legal Delta and its adjacent areas. The Inventory is a reference for the Commission, State and local agencies, and recreation providers in planning, developing, and promoting the Delta as a unique recreation and tourism destination.

Investigating Factors Contributing to Phytoplankton Biomass Declines in the Lower Sacramento River

University of California, Davis (UC Davis) | March 23rd, 2023

Investigating the Role of Snow Water Equivalent on Streamflow Predictability during Drought

American Meteorological Society (AMS) | October 20th, 2022

Snowpack provides the majority of predictive information for water supply forecasts (WSFs) in snow-dominated basins across the western United States. Drought conditions t

Snowpack provides the majority of predictive information for water supply forecasts (WSFs) in snow-dominated basins across the western United States. Drought conditions typically accompany decreased snowpack and lowered runoff efficiency, negatively impacting WSFs. Here, we investigate the relationship between snow water equivalent (SWE) and April–July streamflow volume (AMJJ-V) during drought in small headwater catchments, using observations from 31 USGS streamflow gauges and 54 SNOTEL stations. A linear regression approach is used to evaluate forecast skill under different historical climatologies used for model fitting, as well as with different forecast dates. Experiments are constructed in which extreme hydrological drought years are withheld from model training, that is, years with AMJJ-V below the 15th percentile. Subsets of the remaining years are used for model fitting to understand how the climatology of different training subsets impacts forecasts of extreme drought years. We generally report overprediction in drought years. However, training the forecast model on drier years, that is, below-median years (P15, P57.5], minimizes residuals by an average of 10%in drought year forecasts, relative to a baseline case, with the highest median skill obtained in mid- to late April for colder regions. We report similar findings using a modified National Resources Conservation Service (NRCS) procedure in nine large Upper Colorado River basin (UCRB) basins, highlighting the importance of the snowpack–streamflow relationship in streamflow predictability. We propose an “adaptive sampling” approach of dynamically selecting training years based on antecedent SWE conditions, showing error reductions of up to 20% in historical drought years relative to the period of record. These alternate training protocols provide opportunities for addressing the challenges of future drought risk to water supply planning.