Rocky Brushy Creek Watershed Mgmt. Plan (2007) -- Part 2

CHAPTER 9Furthermore, with increasing development in the region, there will be less permeable land availablefor the rainfall to replenish the groundwater.9.4.1 Aquifer RechargeApproximately half of the Northwest Hillsborough area occupies lands where recharge to theFloridan Aquifer occurs at a rate varying from 1.0 inch to 10 inches per year. This area includes theupper reaches of the Rocky/Brushy Creek Watershed. The remainder of the NorthwestHillsborough area is a discharge area that discharges from the Floridan aquifer at an estimatedrate of 1 to 5 inches per year (SWFWMD, 1996). Figure 9-6 presents the recharge and dischargerates within the Northwest Hillsborough area. Protection of recharge areas in the watershed iscritical to the preservation of the regional groundwater sources and meeting regional water supplydemands.Several management and regulatory strategies have been undertaken in recent years to enhanceaquifer recharge in the Northwest Hillsborough area, which include the following:• Optimization and expansion of existing aquifer storage and recovery systems• Delineation of recharge/discharge relationship• Identification of sites for wetlands, lake, and aquifer rehydration• Identification of opportunities to re-engineer stormwater management systems to enhancegroundwater recharge and improve water quality in waterbodies used for drinking water• Identification of opportunities to use reclaimed water for rehydration• Improvement of wellhead protection ordinances to include recharge areas and landuseordinances• Modification of Environmental Resource Permit (ERP) regulations to enhance aquiferrecharge• Modification of local, state, and District regulations to maintain and enhance groundwaterrecharge9.4.2 Impacts Due to Water WithdrawalsThe literature describing the effects of groundwater withdrawal on wetland hydroperiods and lakestages dates to 1971. Since that time, the nature of the impacts to wetlands has been documentedin wetlands both in and around major wellfields (Rochow, 1998). Generally, symptoms of wetlandhealth decline (e.g., replacement of aquatic plant species by upland species, tree-fall, soilsubsidence, loss of wetland-dependent wildlife) have occurred in the vicinity of large-scalegroundwater withdrawals (e.g., Section 21, Cosme, Northwest Regional, and Eldridge – Wilde, andSouth Pasco Wellfields). As a Water Use Permit (WUP) condition, permit holders have beenrequired to monitor water levels and ecological indicators of wetland viability, and annual reportshave been prepared describing wetland hydrobiological conditions since the mid-1970s. The linkhas been made between groundwater withdrawals and reduced hydroperiod in area wetlands.Under the NTB II project, the SWFWMD has established many more wetland monitoring sites, andrecovery strategy has been developed.9-13 Rocky/Brushy Creek Watershed Management Plan