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ESTIMATION OF WATER USE AND DEMAND
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- WATER MONITORING STREAM DISCHARGE GAUGES
- REAL-TIME GROUNDWATER MONITORING SYSTEM
- POLICY OPTION Real-time groundwater monitoring should be part of the overall monitoring program included in a state water management plan. PRECIPITATION MONITORING
- NATIONAL SOIL MOISTURE DATA
- INTERSTATE SURFACE WATER AND CONTAMINATION TRANSPORT
- MONITOR QUALITY AND FLOW ENTERING AND LEAVING STATE
ESTIMATION OF WATER USE AND DEMANDSURFACE WATER AND GROUNDWATER INTERACTIONSubsurface water movement occurs in two primary environments. The first is in and near the recharge area where aquifers are unconfined or partially confined, groundwater movement is under water table conditions, and groundwater/surface-water interaction is common. In this environment, precipitation infiltrates into the subsurface and moves down gradient and laterally to areas of low topography where the shallow groundwater discharges into streams or as seeps and springs. Groundwater/surface-water interaction is driven by hydraulic head (head) and serves to sustain streams during periods of drought when runoff is absent (groundwater head is higher than surface-water head) and contributes aquifer recharge when stream levels are high (surface-water head is higher than groundwater head). Groundwater discharge to streams forms the base flow component of stream discharge, forms the sustainable flow of contact springs and wetlands, and supports habitat and biota. Subsurface water movement in this environment is generally less than 15 miles and occurs from the updip limit of an aquifer, down gradient to the point where the aquifer is sufficiently covered by relatively impermeable sediments and becomes confined in the subsurface (Cook [and others?], 2014). The second environment is characterized by subsurface water that underflows streams and areas of low topography and moves down gradient to deeper parts of the aquifer. Groundwater in this environment is separated from the land surface by relatively impermeable sediments that form confining layers. Groundwater in the coastal plain can move relatively long distances from recharge areas in aquifers that contain fresh water at depths that exceed 2,500 ft (Cook, 2002). With increasing depth, groundwater becomes highly pressurized and moves slowly down gradient or vertically and laterally along preferential paths of highest permeability. As it moves, minerals are dissolved from the surrounding sediments and accumulate to transform fresh water to saline water. This deep, highly mineralized groundwater eventually discharges into the deep oceans. RECOMMENDATIONDevelop strategies to promote groundwater recharge to maintain historic rates of base flow, including limitations on shallow groundwater production and protection of recharge areas. POLICY OPTIONSDevelop a statewide water management plan that addresses groundwater/surface-water interaction with guidelines for protection of aquifer recharge areas and historic base flows. WATER MONITORINGSTREAM DISCHARGE GAUGESThe CPYRWMA operates and maintains a Flood Warning System (FWS) in southeast Alabama. Currently, 16 electronic stream/precipitation gauge stations and 5 precipitation gauge stations are operated and maintained by the CPYRWMA (fig. 71). The FWS was installed in 1993 by the USACE and is a joint effort of the USACE Mobile District, and the CPYRWMA (CPYRWMA, 2013a). River levels for FWS stations are recorded for the prior 72 hours and can be obtained from the CPYRWMA’s website. Table 26 lists the CPYRWMA stream/precipitation gauge stations, along with corresponding subbasins and watersheds. Stream/precipitation gauges are located in Barbour, Coffee, Covington, Dale, Geneva, Henry, and Houston Counties. Currently, Bullock, Crenshaw, and Pike Counties have no stream gauges, primarily due to the relatively small part of each county included in the CPYRWMA. RECOMMENDATIONSFurther studies should be conducted to rate stream discharge for CPYRWMA flood warning system gauges. Discharge rating would provide discharge volumes for corresponding stage measurements for each stream that could be used for future water resource research and water policy development. The current flood warning system should be expanded with additional stream/precipitation gauges. Some possible locations for expansion include installing a stream gauge on the Yellow River near the confluence of Poley Creek and Lightwood Knot Creek, an upstream gauge at the Shiloh rainfall gauge, the upstream portion of Lightwood Knot Creek in Crenshaw County, and the headwaters of the Pea River in Bullock County. A final recommendation would include downloadable historical rainfall/gauge height data from the CPYRWMA website. REAL-TIME GROUNDWATER MONITORING SYSTEMThe GSA Groundwater Assessment Program (GAP) currently operates and maintains 23 real-time groundwater monitoring systems, monitoring water levels and discharge in various aquifers in wells (21) and springs (2) throughout Alabama. Groundwater levels from wells and discharge for springs are recorded every 30 minutes and transmitted daily to the GSA GAP office (GSA, 2014b? [letter as revised--Periodic Monitoring Program? see comments in ref list]). Hydrographs, based on mean daily water levels are automatically generated, updated daily, and uploaded to the GSA GAP page on the GSA website, which can be accessed at www.gsa.state.al.us/. The GSA GAP currently has three real-time wells installed in the CPYRW (fig. 72). DLE-1, which is located in Dale County, was the first real-time well installed in the CPYRW and is constructed in the Clayton aquifer to a depth of 453 ft below land surface (bls). The GSA GAP maintains a period of record for this well from 1980 to present (fig. 73), although the real-time hydrograph depicts water levels since August 2012, when the real-time system was installed (fig. 74). The hydrograph for DLE-1 also depicts percentile lines based on data from 2000 through 2010 to allow comparison with previous water levels. The real-time monitoring system in the CPYRW was recently expanded with the addition of two new monitoring stations. These two wells were installed in Geneva and Dale Counties, as a cooperative effort between the CPYRWMA and GSA. Well Geneva-1 (real-time system installed in October 2013), in north-central Geneva County, is constructed in the Nanafalia aquifer to a depth of 790 ft bls. Geneva-1 was previously a GSA continuous monitored well with a period of record from 1967 through 1971 and from 1974 through 2012 (fig. 75). Figure 76 shows the hydrograph depicting water levels in Geneva-1 since October 2013. Well DLE-2, located in Dale County, is constructed in the Nanafalia aquifer to a depth of 240 ft bls. The GSA GAP maintains a period of record for this well for 1965, and from 1967 through 1971, and from 1974 to present (fig. 77). Figure 78 is a hydrograph for well DLE-2, which was fitted with a real-time monitoring system in November 2013. Wells Geneva-1 and DLE-2 were selected to demonstrate groundwater-level trends in the relatively deep, highly confined and relatively shallow, partially confined Nanafalia aquifer (figs. 76, 78).
RECOMMENDATIONThe CPYRWMA should cooperate with the GSA to expand the GSA real-time monitoring program in southeast Alabama to aid in determining long-term fluctuations in groundwater levels in response to groundwater withdrawals, land use, and climatic changes. Other monitoring systems should be installed in the CPYRW including climate (temperature and precipitation) and soil moisture. The CPYRWMA should also provide educational outreach in conjunction with GSA to provide information on the GSA’s real-time system. POLICY OPTIONReal-time groundwater monitoring should be part of the overall monitoring program included in a state water management plan. PRECIPITATION MONITORINGAlabama’s climate is classified as humid sub-tropical with mild winters and hot summers (CWP and GSA, 2005). Average annual temperature in Alabama is about 63 degrees Fahrenheit (°F) (Southeast Regional Climate Center, 201___ [a digit omitted—not sure if should be 2013 or 2009; 2012 is previously cited but not listed). Mean rainfall in the CPYRW is 53.4 inches for the time-period 2000 through 2013, based on rainfall data obtained from the CPYRWMA. Rainfall data was tabulated for the years 2000 through 2013 from 21 precipitation gauges maintained and operated by the CPYRWMA (table 27). Rainfall in the watershed is generally well distributed throughout the year, with the driest portion of the year, on average, in September and October; however, drought and years of excessive precipitation periodically occurs (CWP and GSA, 2005). Using the overall mean rainfall of 53.38 inches from 2000 through 2013, drought conditions prevailed in the CPYRW in 2000, 2001, 2002, 2003, 2006, 2007, 2010, and 2011. Excessive precipitation occurred in 2009 with mean rainfall of 77.43 inches. The minimum average annual rainfall of 20.30 inches was recorded in Coffee County at Folsom Bridge Station in 2000. The maximum average annual rainfall of 89.48 inches was recorded in Geneva County at Geneva Station in 2013. RECOMMENDATIONCurrent FWS precipitation gauges should be expanded. These data should be maintained and combined with supplemental data from other precipitation monitoring stations in the CPYRW. These data should be made available to key stakeholders in near real time on the CPYRWMA website. POLICY OPTIONA comprehensive statewide water management plan should be developed to include groundwater, surface water, climate (temperature and precipitation), and soil moisture monitoring systems. NATIONAL SOIL MOISTURE DATAThe USDA NRCS maintains 21 stations in Alabama (fig. 79) to monitor soil moisture, among other parameters, as part of a pilot project for establishing a national soil-climate monitoring program (USDA NRCS, 2004a OR b?). This pilot project, Soil Climate Analysis Network, currently has 191 stations in 40 states (USDA NRCS, 2014). A data logger records soil moisture at depths of 2, 4, 8, 20, and 40 inches and reports the data to the National Water and Climate Center in Portland, Oregon (USDA NRCS, 2004 a OR b?). Currently, there are no soil monitoring stations installed within the CPYRW management area; however, the CPYRWMA can request that stations be installed by contacting the USDA NRCS. RECOMMENDATIONThe CPYRWMA should submit a request to the USDA NRCS for the installation of soil monitoring stations within the CPYRW. INTERSTATE SURFACE WATER AND CONTAMINATION TRANSPORTInterstate surface-water and contamination transport studies have been previously conducted and published by the GSA)(fig. 80). In 2002, the GSA published its assessment of the Yellow River and in 2010 published its assessment of the Choctawhatchee and Pea Rivers. Together, these assessments depict discharge and water quality conditions in the Choctawhatchee, Pea, and Yellow Rivers. Table 28 lists the GSA monitoring sites on the three rivers. Constituents analyzed during the monitoring events included the following: stream discharge, field parameters (stream temperature, turbidity, specific conductance, pH, and dissolved oxygen (DO)), laboratory analyses (nutrients, biochemical oxygen demand (BOD), total dissolved solids (TDS), turbidity, total suspended solids (TSS), inorganic nonmetallic constituents, metals, and bacteria (Cook and others, 2002; Cook and Murgulet, 2010). The USEPA has published standards for primary and secondary drinking water regulations. Primary drinking water standards are enforceable, whereas secondary standards are recommendations only. Primary standards are protective of human health, while secondary standards deal mainly with aesthetic conditions, such as taste, odor, and color (USEPA, 2009). Of the 25 constituents analyzed by the GSA for these prior studies, only five constituents (pH, aluminum, iron, lead, and manganese) exceeded primary/secondary drinking water standards (table 29). The upstream monitoring site (PR1) on the Pea River had an average pH value of 5.9, which is outside the range for secondary drinking water standards (6.5-8.5). The downstream site (CR1) on the Choctawhatchee River had an average pH value of 6.4, which is also outside the range for secondary drinking water standards. Although naturally occurring, aluminum concentrations for all five sites on the Choctawhatchee and Pea Rivers were above secondary drinking water standards (50-200 micrograms per liter (µg/L)), with the highest average concentration at site WCR on the West Fork Choctawhatchee River at 950 µg/L, and the lowest average concentration (212 µg/L) at site CR1 on the downstream segment of the Choctawhatchee River. All six sites on the Choctawhatchee, Pea, and Yellow Rivers had average concentrations that exceeded the secondary drinking water standards for iron (300 µg/L), which is also naturally occurring, with the highest average concentration (744 µg/L) at site WCR and the lowest average concentration (440 µg/L) at site PR3 on the downstream segment of the Pea River. Two sites, PR1 and PR3, had average lead concentrations above primary drinking water standards (15 µg/L), with the highest average concentration (28 µg/L) at PR3. Lead does not occur naturally in this area and is probably present in these watersheds due to atmospheric deposition. Two sites, PR1 and PR2, had average concentrations above secondary drinking water standards (50 µg/L) for manganese. RECOMMENDATIONThe CPYRWMA should cooperate with ADEM to establish a monitoring program to monitor local water quality and maintain a water quality database to identify water-quality trends in the CPYRW. These data should be used to assess stream quality for biological resources, all current and future water users, and stream discharge entering Florida. The CPYRWMA should establish a dialogue with the state of Florida regarding stream discharge entering Florida. MONITOR QUALITY AND FLOW ENTERING AND LEAVING STATEThe GSA published data on the quality of water leaving the state from the Choctawhatchee, Pea, and Yellow Rivers, as discussed in the previous section. The CPYRWMA installed stream gauges at upstream and downstream sites on the Choctawhatchee River, a midstream site on the Pea River, and upstream and downstream sites on the Yellow River, which monitor stream levels in the CPYRW. 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