Performing Department
(N/A)
Non Technical Summary
This project aims to improve irrigation water conservation in dry-climate agricultural regions. To achieve this goal, the team will investigate the use of solar panels to suppress evaporation from irrigation storage and conveyance systems. The focus will be on the Rio Grande Valley (RGV) of Texas, an underserved agricultural region that is home to >1.3 million people. Irrigation is critical to sustain agricultural productivity andaccounts for ~80% of total freshwater withdrawals in the semi-arid RGV.Yet high irrigation needs, climate change and a burgeoning population growth are straining the region's water resources.Through this Seed Grant, the project team will develop a preliminary analysis of opportunities, benefits and challenges associated with covering irrigation reservoirs, human-made ditches, and natural channels (i.e., ancient secondary river channels) with solar panels in the RGV. This includes mapping and consolidating data on irrigation storage and conveyance systems, developing scenarios with solar energy generation potential and limitations, and assessing irrigation water losses and quality to determine potential co-benefits from irrigation-solar co-location. The outcomes of this Seed Grant will position the team to pursue follow-on funding for a larger project that will further evaluate specific co-benefits, engages stakeholders, and encompasses logistical, social, and economic dimensions of co-locating irrigation infrastructure and solar power.
Animal Health Component
0%
Research Effort Categories
Basic
20%
Applied
80%
Developmental
(N/A)
Goals / Objectives
To support our long-term, follow-on goal of leveraging solar power to improve irrigation water sustainability while promoting decarbonization in the semi-arid Rio Grande Valley, we set four specific aims for this Seed Grant:Consolidate data on irrigation storage and conveyance systems.Assess current water losses from uncovered irrigation storage and conveyance systems.Evaluate the water quality of uncovered irrigation storage and conveyance systems.Determine opportunities and challenges for co-locating solar power and irrigation infrastructure.
Project Methods
Geospatial analyses.We will map the total surface area and volume of irrigation storage and open-channel systems in the RGV. We will consolidate existing geospatial datasets, such as those made publicly available by the Irrigation District Engineering and Assistance program of the Texas A&M Agrilife Extension Service, which will be complemented by a new, updated set of geospatial analyses.Specifically, we will classify and map the extent of all types of irrigation systems that are directly subject to evaporative losses, including artificial (irrigation ponds and reservoirs) and natural (resacas) storage and conveyance infrastructure. We will also synthesize data on water withdrawals for irrigation and other purposes in the RGV, which are available from USGS, and consolidate available data from the >25 irrigation districts of the region, as well as public utility companies. In addition to mapping the spatial footprint of irrigation systems, these data will allow us to analyze trends in irrigation water use over time and run projections into the future.Water losses. We propose to evaluate which of two broad approaches to estimating hydrologic losses in irrigation systems will yield the most cost-effective and useful data that could be extrapolated across the RGV. The first approach focuses on the feasibility and effectiveness of additional gages designed to provide point estimates of evaporation (using evaporation pans) and infiltration/seepage (using infiltrometers) at hydrologically distinct areas of the RGV's irrigation network--including human-made and natural reservoirs and conveyance mechanisms (irrigation canals and resacas). The second approach would center on monitoring these systems from a small-scale, precise water-balance approach. This method might yield sufficiently useful estimates of hydrologic abstractions as a combined, single parameter at a significantly lower cost than an extensive network. This second approach would focus on candidate testbeds among the various reservoirs, human-made ditches, and natural irrigation conveyance systems across the RGV. We will use evaporation pans and infiltrometers to take field measurements while evaluating these two approaches. We will compare field measurements with modeled evaporation rates computed through well-established equations that use climatological input data, such as solar radiation, air temperature, water vapor pressure, wind speed, and elevation.Water quality.We will consolidate existing data from irrigation districts and public utility companies and conduct additional field work to measure water quality parameters in irrigation reservoirs, open canals, and resacas. We are particularly interested in determining the trophic status of irrigation water in the RGV. To create a baseline for follow-on studies and funding, we will evaluate the water quality of irrigation reservoirs, open canals, and resacas. We will bi-monthlysample 20-30 sites during the 2-year period of this Seed Grant. We will use a multiparameter sonde to measure chlorophyll-a, turbidity, pH, conductivity, temperature, and dissolved oxygen. We will also grab samples to measure nitrate, ammonia and, ortophosphate, andtotal phosphorus using a spectrophotometer. Finally, we will measure fluxes of CO2, methane and nitrous oxide using portable greenhouse gas analyzers.Solar energy opportunities. This part of the project will build on the geospatial analyses.To estimate the technical potential for solar power generation (or 'installed capacity', in MW), we will use published data on the power density (MW km-2)of floating solar power compiled by the National Renewable Energy Laboratory (NREL). Technical potential data will be transformed into actual solar energy generation (MWh per year) using NREL's PVWatts Calculator, a free application for estimating the energy production and cost of energy of grid-connected solar power systems throughout the US. In addition to creating scenarios with solar energy generation potential, we will evaluate pros and cons associated prospective locations, considering other uses that may conflict with solar energy generation (e.g., recreation and fisheries in reservoirs and resacas), as well as logistical constraints, such as proximity to the electrical grid. The analysis of water losses will allow usto develop preliminary quantifications of water conservation benefits from covering irrigation infrastructure with solar panelsin the RGV.