Laserfiche WebLink
• Two methods of estimating evapotraspiration (ET) were investigated: <br /> a. The MODFLOW ET package which is set up to vary the amount of ET based on the <br /> depth to ground water where the greater the depth to groundwater, the less the ET. <br /> Three separate ET zones; riparian, meadow and sand hill, were modeled <br /> b. ET is held constant with depth for each of the three zones. Holding ET constant with <br /> depth allows for the applicant to consistently reproduce URFs for well depletions and <br /> recharge accretions. Otherwise, depletions and accretions would need to be calculated <br /> each year by the model using actual stream levels. <br /> • Calibration data for the model consists of water level elevation data. NCWCD has <br /> maintained a database of water level measurements from selected monitoring wells which <br /> formed the basis for the calibration. Water level measurements from 27 to 35 wells at 13 <br /> different time periods, for a total of 415 calibration points, were used in calibrating the <br /> model. <br /> The following updates were made to the original model: <br /> • Minor revisions were made to Recharge Well #1 pumping from 1997 to 1999 (CDOW, <br /> January 9, 2004). <br /> • The model time span was expanded through 2004. For the expansion, two time periods <br /> • were added to the calibration increasing the total number of calibration points to 466 <br /> (CDOW, September 15, 2004). <br /> • Minor revisions were made to the locations of Recharge Ponds 3 and 6 (CDOW, <br /> September 20, 2004) <br /> 4.2 Aquifer Performance Testing <br /> Two Aquifer Performance Tests (APTs) were conducted at existing recharge wells located west <br /> (upstream) and east (downstream) of CDOW's Tamarack Ranch State Wildlife Area (SWA). <br /> The primary objective of the APTs was to investigate the impact of streambed characteristics on <br /> aquifer well pumping near the Lower South Platte River. A testing protocol was prepared by <br /> CDOW documenting testing procedures for the APTs (See Appendix A). This protocol was <br /> reviewed and accepted by the following interested parties prior to testing: NCWCD, TZA, <br /> Hydrosphere, and W &EST. <br /> Representatives of TZA, NCWCD and CDOW ran the field operations. Representatives of <br /> W &EST and Hydrosphere were present during the majority of both APTs and monitored testing. <br /> • <br /> 10IPage <br />