Evapotranspiration Network Design: Implementation Plan Development

Accurate measurement of climate variables via the optimal number and location of ground sensors is important to accurately compute evapotranspiration over a large area. Optimal ground sensor networks for each of the four evapotranspiration (ET) parameters (solar radiation, air temperature, relative humidity, and wind speed) were developed independently. The goal of this project was to develop an implementation plan for the ET monitoring network that would incorporate the results from the four indicated meteorological variables for the South Florida Water Management District (District). The implementation of a network design involves assignment and placement of the sensors. The assignment of the sensors depends on the existing number of sensors and the required number of sensors for the optimal design. The placement of sensors depends on the practical considerations and the logistics related maintenance and installation options. The implementation strategies were identified and an implementation plan matrix was developed which included five implementation plans based on the available District owned and non-District sensors. The potential opportunities to avoid land acquisition and to assume ownership of the non-District stations were identified and incorporated into the evaluation process. Preliminary planning level cost of land acquisition, installation, maintenance, and others were estimated for installation of new and relocation of existing sensors within and across the analysis blocks were prepared. The previously designed optimal networks for all the variables were compiled to 50 analysis blocks of 32 km x 32 km uniform grids. A total of 75 full weather stations are necessary to satisfy the design requirements of all four networks. Based on cost and logistics of sensor locations, Alternative 5 is recommended as the preferred implementation plan that would meet the required sensor density recommended in the previous network design studies. The recommendation included 42 existing full weather stations (25 stations owned by SFWMD, 11 stations owned by FAWN, and 6 stations owned by NOAA), relocation of 5 District owned stations, 13 existing partial weather stations owned by NOAA that would be upgraded to full stations, 11 existing rain gauge stations owned by various counties that need to be upgraded to full stations, 9 new stations. Six of these stations would need land acquisition.