Submitted by: Tracy Slavin, Regional Resources, MP-400, 916 978-5202, TSLAVIN@mp.usbr.gov
Proposal ID: 923
| Title |
| Tools to assess seasonal wetland best management practices for water conservation and salinity management using high resolution remote sensing, direct evapotranspiration monitoring and modeling |
| State the Problem. How Do Your Research Outputs Contribute to Achieving Reclamation's Mission, and The S&T Program Mission and Performance Measures? | The Central Valley Project Improvement Act (CVPIA) requires that Reclamation develop criteria for evaluating water conservation plans prepared by San Luis Unit contractors. The criteria for agricultural and urban water contractors have already been established, however little progress has been made on development of similar criteria for public wetlands. Much of failure can be attributed to lack of analytical tools with which to quantify the water needs of various moist soil plants within each wetland area. An important factor in determining wetland water needs and best management practices is accurate measurement of moist-soil plant evapotranspiration. Hydrologic water balances have not been used to good effect to back-calculate moist soil plant evapotranspiration because of a lack of good field inflow and outflow data and a failure to be able to quantify the areal extent of component wetland moist soil plant species. Monitoring of water deliveries and drainage return flows is generally poor and inconsistent throughout the Grasslands Ecological Area. Where water quality data is available, water balances can be supplemented with salinity balances which can act as a check on wetland direct evaporation and evapotranspiration estimates. Quantification of seasonal wetland hydrology will be critical in the assessment of the effectiveness of various seasonal wetland practices to meet San Joaquin River salinity objectives. Documentation of wetland best management practices is now a Reclamation requirement for continued water delivery. The research conducted to date has taken advantage high resolution (2 meter) imagery from the IKONOS and Quickbird satellite systems and more recently in FY 2007 and FY 2008 even higher resolution imagery (15 cm) from airborne cameras. We have developed algorithms with the ability to match spectral signatures to individual moist soil plant species with a high degree of reliability for certain broad classes of vegetation. These techniques have been field-verified by ground truthing of moist soil plant associations located in the private, state and federal wetlands. Flown or satellite data is available for every year between FY 2004 and FY 2008. Current collaborative research, that was started in FY 2005 on six-paired wetland sites in the state and private wetland areas, is directed at improving understanding of the impacts of salinity management practices, such as delayed drawdown, on the long-term ecological health and sustainability of the wetlands. A Bowen weather station was borrowed from the USDA-ARS and set up adjacent to one of the wetland pairs - this station has been operated since 10/1/2006. ET estimates have been made at this weather station for swamp timothy and this data used with ResET to estimate moist soil plant ET within the six paired wetland sites (in the State and private wetland areas). Swamp timothy management is practiced in all of these areas. The ResET program requires thermal data in order to determine "hot" and "cold" pixel values - which are then associated with current pan evaporation data. Flow data obtained from the 6-paired wetland sites was not adequate for the development of accurate water balances owing to periodic board adjustments at the drainage outlets that went unrecorded by State Wildlife Management Area staff. An additional problem was the substitution of "V" notch weirs for the more typical weir boards - which confused water management staff who relied upon previous year settings. These problems were solved in FY 2008 by purchasing acoustic doppler sensors to replace the "V" notch weirs and continuous stage recorders. Work tasks for FY 2009 will include flying thermal IR data for the wetland site containing the weather station and using the more accurate flow data from the new instrumentation to calculate wetland ET by mass balance. ResET will be used to estimate ET using the thermal IR data and results compared. |