Grantee Research Project Results
2017 Progress Report: Assessment of Stormwater Harvesting via Managed Aquifer Recharge to Develop New Water Supplies in the Arid West: the Salt Lake Valley Example
EPA Grant Number: R835824Title: Assessment of Stormwater Harvesting via Managed Aquifer Recharge to Develop New Water Supplies in the Arid West: the Salt Lake Valley Example
Investigators: Dupont, R. Ryan , McLean, Joan E , Jackson-Smith, Douglas , Peralta, Richard , Null, Sarah
Current Investigators: Dupont, R. Ryan , McLean, Joan E , Null, Sarah , Peralta, Richard , Jackson-Smith, Douglas
Institution: Utah State University
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 2015 through August 31, 2018 (Extended to August 31, 2020)
Project Period Covered by this Report: September 1, 2016 through August 31,2017
Project Amount: $749,998
RFA: Human and Ecological Health Impacts Associated with Water Reuse and Conservation Practices (2014) RFA Text | Recipients Lists
Research Category: Human Health , Water
Objective:
The project is designed to test the hypothesis that Managed Aquifer Recharge (MAR) via Green Infrastructure (GI) systems for stormwater harvesting is a technically feasible, socially and environmentally acceptable, economically viable, and regulatorily achievable option for developing new water supplies for arid Western urban ecosystems experiencing increasing population, and climate change pressures on existing water resources
Progress Summary:
Research Component 1, Monitoring of Existing MAR/GI Stormwater Management Systems Based on existing MAR/GI system monitoring that has taken place during Year 1, a wide range of pollutant concentrations result when data from a range of rainfall events are combined even at a specific site. For the three sites treating primarily pavement runoff (300 East and the Early Childhood Education Building, Utah State University(USU), in Logan, and the Salt Lake City Public Utility parking lot site), overlapping 95% Confidence Intervals of measured runoff pollutant concentrations during Year 2 showed differences among sites for TN and Cr (Public Utilities and Early Ed being higher), TDN, TP and TDP (higher at the Early Ed site), and Cu and Pb (higher at the Public Utility site) under similar rainfall events. Many of the MAR/GI systems being monitored appear to be releasing contaminants to underlying soils. The 300 East bioswale continues to release dissolved solids as indicated by elevated EC values, and continues to be a net producer of low concentrations of dissolved arsenic. Filter media used at a bioretention site continues to release nitrate, EC, Al, Cr, Ni, As, and Cd. UteLite Expanded Shale generally performs better than the construction pea gravel, but does not provide metal and nutrient uptake that is claimed by the supplier. A vegetated parking strip showed increasing concentrations of ammonia and Al, Fe, and Ni with depth. The one bright spot in Year 2 monitoring results is the dry well infiltration system on the USU campus that is yielding an average 68% removal of all pollutants being analyzed in the study.
Research Component 2, Integrated Modeling
The use of historic Red Butte Creek direct runoff was evaluated to recharge a principal water supply aquifer near the mouth of Red Butte Canyon via a grassed infiltration basin. It was predicted to take about 3 months for significant percolating water to reach the water table of the principal aquifer. The Stakeholder Advisory Committee (SAC) is not in favor of the idea of injecting stormwater, without significant treatment, into a water supply aquifer. In addition, the SAC cited water rights and environmental regulatory concerns. The SAC was in favor of exploring the possibility of injecting newly captured stormwater into a shallow aquifer not used for culinary water supply, where the water table is close to the ground surface and the recharge could provide secondary water supply. The best sites to explore for recharging aquifers using stormwater from new low impact development and GI would: (a) be in the central portions of Salt Lake Valley where the water table of the shallow aquifer is close to the ground surface, (b) have sufficient unsaturated zone thickness to permit needed recharge mounding, and (c) have sufficiently slow groundwater flow velocity that all or most of the recharge water could be captured and extracted for secondary water use.
Research Component 3, Social Science Research
In Utah, there appears to be a number of serious social, political, and legal obstacles to using deep dry wells as a means to recover stormwater through managed recharge to deep aquifers. There are fewer concerns about approaches that rely on infiltration and recharge of shallow (non-culinary) aquifers. As a result, the modeling team has shifted its focus to develop tools that could help cities and developers identify the optimal spatial configurations of distributed shallow stormwater infiltration and recovery systems for secondary water use. The team is also working to clarify the legal status of water rights associated with recovery of shallow infiltrated stormwater in Utah.
Future Activities:
Samples from field demonstration sites will be collected to allow comparison of the performance of GI/MAR systems as a function of vegetation type across turf and a range of common GI plant species (cattail, sedge, sunflower, baltic rush, inland salt grass, and bunch grass species). Additional roof and dry well samples, and samples from a vegetated parking strip will be collected to evaluate steady-state pollutant removal potential from these MAR/GI systems. A green roof will be instrumented to evaluate water quality improvements provided by that roof treatment compared to conventional roofing materials.
The relationship between elevated DOC and arsenic mobilization continues to be explored at a number of these field demonstration sites to determine the predictability of potential arsenic mobility in MAR/GI stormwater management systems in Utah. Disaggregation of pollutant loading data will continue to explore relationships between pollutant concentrations and storm intensity and duration using rainfall data available from each of the field sites.
As a result of the first Year 2 meeting with the Stakeholder Advisory Committee (SAC), the integrated modeling effort has been redirected. Simulation of stormwater injection via deep wells has been replaced by prioritization of model development for MAR/GI shallow infiltration systems because of initial concerns over groundwater contamination potential, and any aquifer recharge and recovery was strongly recommended to be limited to use in secondary water systems. Aquifer recharge scenarios will consider locations where, after stormwater injection, it would be practical and legal to extract injected water for secondary water use. There was also a desire to provide modeling and model scenarios at a much smaller scale than relevant for watershed planning. A more localized Stormwater-MAR model will be constructed to compute aquifer recharge and recovery for a development sized planning area (i.e., 40 to 80 ac).
The calibrated and validated WINSLAMM model will be applied to a much larger (25 square mile), much more diverse land use area in the Salt Lake watershed discharging to the Jordan River to assess changes in runoff volume and pollutant loading from MAR/GI implementation strategies. WINSLAMM generated runoff/pollutant load changes serve as inputs to the vadose zone/groundwater and Red Butte Creek and Jordan River surface water quality models. The coupled simulation models will be used to evaluate the robustness of different management strategies and to analyze the ecosystem services tradeoffs between water quantity and water quality changes driven by different MAR/GI implementation strategies.
Beginning December 2017, data from the online survey of stormwater managers in MS4 permitted cities will be collected and analyzed. In the summer of 2018, focus groups with neighborhood residents will be organized. The social science team will organize a ½ day participatory modeling workshop retreat tentatively planned for May 2018, to provide a hands-on opportunity for the SAC to explore the capabilities of the draft integrated systems models.
References:
Prudencio, L., and Null, S.E. 2017. Stormwater Management and Ecosystem Services: A Review. Submitted for publication to Environmental Research Letters, October 22, 2017.
Dupont, R. and J. Draper. 2016. Beyond the Ivory Tower: University-Stakeholder Partnerships. Presented to the 2016 Stale Lake County Watershed Symposium, West Valley City, UT. November 16.
Dupont, R. and T. Rife. 2016. Green Infrastructure for Stormwater Harvesting and Pollutant Removal. Presented to the Utah Section of the American Public Works Association, Sandy, UT. October 12.
Dupont, R. and E. Fairchild. 2017. Assessment of Stormwater Harvesting via Manage Aquifer Recharge to Develop New Water Supplies in the Arid West: The Salt Lake Valley Example. Presentation to the Utah Stormwater Advisory Coalition, Salt Lake City, Utah. March 7.
Dupont, R. 2017. Green Infrastructure/Low Impact Development for Improved Management of Stormwater. Presented to the Rural Water Technology Alliance Water Technologies Information Conference and Annual Training, Provo, UT. March 8.
Limbu, S.B., and R.C. Peralta. 2017. Mass Balance Evaluation of Lower Knowlton Fork (LKF) Watershed, Salt Lake County, Utah. Poster presented at the 2017 Spring Runoff Conference, Logan, UT. March 28.
Prudencio, L., and Null, S.E. 2016. Stormwater Management and Ecosystem Services: A Literature Review. Poster presented to the American Geophysical Union Fall Meeting, San Francisco, CA. December.
Rife, T., and R. Dupont. 2017. Evaluation of Bioretention Media Performance at the Salt Lake City Public Utility Site. Poster presented at the 2017 Spring Runoff Conference, Logan, UT. March 28.
Journal Articles:
No journal articles submitted with this report: View all 22 publications for this projectSupplemental Keywords:
vulnerability, TDS, habitat, indicators, sustainable development, public policy, cost-benefit, engineering, social science, ecology, hydrology, environmental chemistry, Great Basin, agriculture, industry, commercial, residential, stormwater, aquifer recharge, groundwater, green infrastructure, ecosystem services, modeling.Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.