Report Proposal Status:
Original 2 pager First Update: 00/00/00 --changes marked in red print
Second Update: 00/00/00 --changes marked in green print
Principal Aquifer:
Aquifer Name(s ): BARA - Basin and Range / California Aquifers; Rio Grande, Colorado River and Great Basins (MRB 6); California River Basins (MRB 8)
Lead Contact: Sue Thiros
Proposed Report Title: Temporal and spatial trends in dissolved solids and salt increases in ground-water and surface-water resources
Scope:
This study will use existing NAWQA water chemistry data, other USGS data (water chemistry, streamflow, water use), and data from water providers, wastewater facilities, other sources to determine trends in dissolved-solids concentrations and increases in salts in ground-water and surface-water resources of basins in the arid and semiarid Western U.S. The study would encompass the Rio Grande, Colorado, Great Basin, and California Rivers, and the Basin and Range and California Aquifer NAWQA synthesis regions that have study units (CAZB, GRSL, NVBR, RIOG, SOCA, UCOL) which have an arid to semiarid climate, have similar land and water-use practices, and face the possibility of salt accumulation issues. We understand that NAWQA is developing separate regional synthesis reports for ground water and surface water; however, the issues of salinization of ground water and surface water in the arid and semiarid west are inextricably intertwined. Thus, we are proposing that this report encompass both ground water and surface water and that the Ground-Water and Surface-Water Status and Trends teams split the cost of funding this report.
Study Units: CAZB, GRSL, NVBR, RIOG, SOCA, UCOL. Due to funding constraints, two study units were dropped out of the analysis. The SANJ and SACR were chosen as the two to drop because they are less arid and have more outflow than other study units, which reduces the risk/potential for salt accumulation problems. In addition, salt balances would be more difficult, uncertain, and costly to develop because outflow is more complex for these study units.
Time Period: About 1900 to present with emphasis on 1975-present
Land Use(s): Agricultural, rangeland, urban
Inter-Regional Principal Aquifer Proposal? Yes/No: Explain: Yes – and interdisciplinary because of the interconnections of dissolved solids in ground water and surface water. The study includes regional synthesis of California and Basin and Range Aquifers, and Rio Grande, Colorado, Great Basin, and California Rivers.
Constituents:
Expected Authors:
Lead: David Anning
Contributing: Steve Gerner, Nancy Bauch, Stephanie Moore, Don Schaefer, Scott Hamlin, and other GW and/or SW specialists from each study unit
Objectives:
Data Interpretation Approach and Feasibility:
Number of sites will depend on data availability and is also commensurate with funding. Dissolved-solids concentration data will be the focus of this study.
Number of Sites/Components (e.g., nutrients, pesticides):
Methods:
The following approach and methods will be used for spatial and temporal trend analysis and characterization of salt increases:
Data Availability and Processing:
Dissolved-solids concentration for ground water and surface water and streamflow data are readily available in USGS and other agency databases.
Staff Availability: The staff is available from among the respective study units.
Complexity: The investigation will require moderately complex data interpretation and analysis. Report staff have experience in investigating dissolved solids in ground and surface water and have performed trend analyses and developed salt balances at local and regional scales for previous USGS reports.
Risks/Contingencies: Development of the salinization-potential maps is dependent on the strength of the relation of salinity to explanatory variables. There may not be very many wells with time series of dissolved solids data. While this may preclude broad statements about conditions about large aquifers, knowledge about the lack of temporal monitoring ground-water resources is of value.
Other Program Contacts: Other western NAWQA study unit staff, National Synthesis team staff, Bureau of Reclamation, Phoenix (have developed a salinization study of central Arizona), some cities may be contacted for wastewater, water-use, and other data. Coordinate with Jacquie Nolan for the Wastewater Data pilot study. An attempt will be made to link this study with other agencies and possibly develop additional sources of funding.
Expected Outcome:
Temporal trends in dissolved-solids concentrations and loads in streams are expected to result from climate fluctuations and/or changes in land and water use. Concentrations and loads of dissolved solids in streams are expected to increase downstream in major river basins as a result of land use and hydrogeology. Concentrations of dissolved solids in ground water are expected to increase in places with agricultural and/or urban land and water use. It is expected that there is significant salt accumulation in ground water in these areas.
Why is this topic important to report on?
Salt accumulation affects the long-term viability of irrigated agricultural and the quality of current and future drinking-water supplies in the arid and semiarid Western U.S. The report developed from this study will provide water managers, cities, counties, and other local and regional entities with information that can be particularly useful for long-term planning by describing the processes that contribute to salinization and identifying areas that are being salinized or that have the potential to be salinized by current land-use and water-use practices. The ability to anticipate future changes in ground-water and surface-water quality will provide an opportunity for communities to mitigate or plan for poorer water quality.
Why does this topic need to be addressed now?
Rapid population growth in the west and the resulting development of water resources and increased reliance on reclaimed water is expected to exacerbate salinity problems. While most of the population growth is occurring in the lowlands, there is also an increase in rural development in mountainous, headwater areas by city dwellers seeking vacation and retirement homes. The resulting increase of water use near the headwaters may degrade water quality for the downstream communities. On a larger scale, development of unallocated surface-water in the upper Colorado River basin may result in higher salinities in the lower basin, where concentrations are already high and are a well-known issue. Characterizing salinization now may bring early (or additional) attention to the problem and allow for early development of solutions to slow, mitigate, or even prevent salinization.
Why is it appropriate for this topic to be addressed by the USGS? NAWQA? This Regional Team?
Salinization of ground-water and surface-water resources is a regional issue for the western US. The USGS, through the NAWQA and other national and district programs, has consistent regional-scale data sets, long-term records, and technical staff to best address this problem. This investigation fills a gap in the synthesis of NAWQA data because there are no focused investigations on dissolved-solids data by a national synthesis team. Within this NAWQA team, we have experts on the hydrologic systems and water quality of the proposed study areas. State agencies are not suited to study multi-state regions, and other federal agencies do not have the unbiased, nonregulatory status, nor the data and breadth of technical expertise of the USGS. Claire Zucker, of the Pima County Association of Goverments (PAG), points out:
“… the project is appropriate for the USGS to pursue because salinization of groundwater and surface water will be affecting many regions in the western United States. A federally initiated project will encourage information sharing between many geographic areas, thereby assisting local and regional governments in their decision making processes.” (letter dated 1/15/2004)
Who cares and why?
Fast-growing municipalities (i.e., Phoenix, Los Angeles, Salt Lake City, Las Vegas, Albuquerque) in the West that face the issue of serving their citizens acceptable drinking water are the main audience as well as other Federal agencies with water-resource responsibilities (i.e., BOR, BLM, etc.) Municipalities are competing not only for water rights, but also for rights to good quality water. Many cities and other municipal water-use organizations are becoming increasingly concerned about salinization of their water supplies. Says Ralph Marra of Tucson Water:
“The proposal is consistent with concerns being raised in a number of southwestern communities regarding the observed and projected increase in salinity in sources of supply over time. Tucson is just beginning to go down this path with its importation of Central Arizona Project water and its increasing reuse of effluent as a major source of supply. This proposed regional study will add both technical substance and stature to the on-going discussion .” (Email dated 01/13/2004)
Agricultural communities that wish to continue their livelihood and are concerned about the potential salinization of their farmland may also be interested in the results of this study. Concerns at the local level have led to conferences, such as the “Emerging Water Salinity Issues Forum” held in July of 1999 in Phoenix, AZ, by the Phoenix BOR office. Says Thomas Poulson of that office:
“This study has the backing of the local reclamation office and the members of the Central Arizona Salinity study. Some of this information is exactly what we are trying to determine at this point.” (Email dated 1/12/2004)
Claire Zucker of PAG comments on salinity and sustainability: “Over the last several years, PAG staff have participated in several public meetins where the topic of salinization of our water resources has been emphasized. In addition, PAG’s Environmental Planning Advisory committee and its subcommittees have identified “reaching safe yield and ensuring a sufficient and good water supply” as one of the priority issues for the region. It is our opinion that stakeholders are concerned about the long term effects of salinization, but the topic is not fully understood or well quantified.” (Letter dated 1/15/2004)
On a regional level, salinity of the Colorado River is an issue that has been recognized for a long time and is the focus of the Bureau of Reclamation’s Basinwide Salinity Program and also the Colorado River Salinity Control Forum. Concern at the national level has led to the “2003 National Salinity Management and De-Salinization Summit” held December 2003 in Las Vegas, Nevada. At an international level, Minute 242 of the International Boundary and Water Commission (1972) requires that water delivered from the U.S. to Mexico through the Colorado River must meet specific water-quality criteria for salinity.
Selected References:
Budget:
Costs associated with this report are mostly labor for data compilation, analysis, and report writing. Costs also include assistance from other western NAWQA study unit personnel and assistance from support staff for GIS needs and preparation of the report for publication. A small portion of the budget is for staff travel so that they can meet to discuss and plan the study and report. Because the study is for regional synthesis of both major river basins and major aquifer systems, costs will be shared. Budget details are provided in the GW status and trends and cycle2 analysis and reports spreadsheet. A summary of suggested gross funding is provided below: