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W. M. Woodham

Publications and source records attributed to W. M. Woodham.

17 recordsLinked to original sources
USGS1996

The effect of discharge and water quality of the Alafia River, Hillsborough River, and the Tampa Bypass Canal on nutrient loading to Hillsborough Bay, Florida

Techniques to measure discharge and nutrient loads in the tidally affected portions of two major rivers tributary to Tampa Bay, the Alafia River and the Hillsborough River, were developed and tested. Discharge, water quality, and total phosphorus and total nitrogen loads for the period April 1, 1991, through March 31, 1992, were evaluated and compared with discharge,water quality, and loads at long-term, nontidal gages in the basins. Long-term discharge and water-quality characteristics at selected sites in the Alafia river and Hillsborough River basins were evaluated. A long-term, decreasing trend in annual-mean discharge was observed for discharges at the Alafia River, Sulphur Springs, and Hillsborough River. Low-flow and high-flow characteristics in the Alafia River and Hillsborough River have changed as well. The decreasing trend in the Alafia River discharges is not due to deficient rainfall but probably is due to decreased ground-water inflow to the river because of long-term declines in the potentiometric surface of the Upper Floridan aquifer. Daily-mean discharges at the mouth of the Alafia River were more variable than discharges at the long-term gage upstream. Daily-mean discharge near the mouth of the river was negative at times, indicating a net loss of water from the river. Daily-mean discharge from the Hillsborough River was minimal from Apil to May 1991, and from late September 1991 to March 1992. During these periods, discharge from Sulphur Springs was a major source of freshwater to the tidally affected reach of the river. Concentrations of total phosphorus and orthophosphorus in the Alafia River above Lithia Springs were the greatest in the 1960's and have generally declined since then. Total nitrogen concentrations have been declining since about 1981. However, increases in nitrate plus nitrite nitrogen concentrations are occurring in Lithia Springs, a second-magnitude spring that flows into the Alafia River. Specific conductance of water discharging from Sulphur Springs to the Hillsborough River has increased from about 124 to more than 2,000 microsiemens per centimeter since 1945. Water quality at the mouth of the Alafia River and Hillsborough River is the result of mixing of freshwater and estuarine water from Hillsborough Bay. Large daily variations in water quality occur at these site because of tidal currents, and vertical stratification of specific conductance is a common feature. Concentrations of phosphorus, nitrate plus nitrite nitrogen, organic carbon, and silica are inversely related to specific conductance at the mouth of the Alafia River. Constituent concentration and discharge data were used to compute loads during the study period. Average daily phosphorus loads were 2.4 tons per day at the mouth of the Alafia River; 0.35 ton per day at the mouth of the Hillsborough River; and 0.06 ton per day at the Tampa Bypass Canal. Average daily nitrogen loads were 1.7 tons per day at the mouth of the Alafia River; 0.86 ton per day at the mouth of the Hillsborough River; and 0.26 ton per day at the Tampa Bypass Canal. The greatest annual loads of phosphorus and nitrogen from the major tributaries to Hillsborough Bay are from the Alafia River, with the greatest loads at the river mouth. Total phosphorus load from the Alafia River was about 894 tons during April 1991 through March 1992, more than six times greater than phosphorus loads form the Hillsborough River. Annual total nitrogen load at the mouth of the Alafia River was about 630 tons, two times greater than at the mouth of the Hillsborough River and more than six times greater than loads from the Tampa Bypass Canal. Basinwide yields of total phosphorus during April 1991 through March 1992 were about 2 tons per square mile at the mouth of the Alafia river basin and were about 0.2 ton per square mile at the mouth of the Hillsborough River. Total nitrogen yield was about 1.5 tons per square mile at the mouth of the Alafia River and about 0.5 ton per s

Water-Resources Investigations Report↗
USGS1996

Evapotranspiration from areas of native vegetation in west-central Florida

A study was conducted to evaluate the suitability of three micrometeorological methods for estimating evapotranspiration from selected areas of native vegetation in west-central Florida and to estimate annual evapotranspiration from areas having a specific vegetation type. Evapotranspiration was estimated using the methods of energy-balance Bowen ratio (EBBR) and eddy correlation. Potential evapotranspiration was computed using the Penman equation. Field measurements were made intermittently from February 1988 through September 1990. The EBBR method was used to estimate evapotranspiration from unforested and forested sites. A mean-gradient Bowen ratio system was used to measure and average vertical air temperature and vapor-pressure gradients, and the Bowen ratio was computed using the mean air temperature and vapor-pressure gradients. The Bowen ratio estimated in this manner was then used to compute evapotranspiration by the EBBR method. Computations that were based on objective review criteria indicated that the Bowen ratio that was computed using measurements that were made using the mean-gradient Bowen ratio system was not always realistic. During a period of extended operation at a dry prairie site, 9 percent of measured available energy during the daytime occurred when the Bowen ratio obtained using the mean-gradient Bowen ratio system was unrealistic. During 5 out of 14 days of continuous operation at a marsh site, more than 30 percent of measured available energy during the daytime occurred when the Bowen ratio obtained using the mean-gradient Bowen ratio system was unrealistic. One of the primary causes of unrealistic Bowen ratios at the unforested sites was condensation of moisture within the tubing of the mean-gradient Bowen ratio system. Measurements made using the mean-gradient Bowen ratio system at a forested pine flatwood site indicated that vapor-pressure gradients were too weak to be resolved by the system. As a result, the Bowen ratio computed for the forested sites was unreliable when it was obtained using the mean-gradient Bowen ratio system. Direct estimates of sensible and latent heat flux that were computed from eddy correlation measurements were generally insufficient to account for measured available energy at all sites. Analysis of eddy correlation and energy-balance data indicated that the sum of sensible and latent heat fluxes accounted for 68 percent of available energy at dry prairie and marsh sites, 74 percent of available energy at a pine flatwood site, and 45 percent of available energy at a cypress swamp site. Because specific causes of the energy-balance discrepancies could not be quantified, corrections to the direct eddy correlation flux estimates could not be made, and eddy correlation data were combined with other energy-balance data to yield two alternative evapotranspiration estimates. The first alternative evapotranspiration estimate was computed by combining sensible heat flux obtained from eddy correlation with measurements of available energy to compute latent heat flux as the residual of the equation for the surface energy balance. The second alternative evapotranspiration estimate was computed by using direct sensible and latent heat flux estimates that were obtained from eddy correlation measurements to compute the Bowen ratio. The Bowen ratio obtained from eddy correlation measurements was then combined with measurements of available energy to compute evapotranspiration by the EBBR method. Of the three alternative evapotranspiration estimates that were obtained from eddy correlation measurements, the estimate that was computed using the EBBR method, with the Bowen ratio computed from eddy correlation measurements, agreed most strongly with the corresponding evapotranspiration estimate that was computed using the EBBR method with the Bowen ratio obtained from the mean-gradient Bowen ratio system. It is probable that actual evapo-transpiration was within a range defined by the standard eddy correlation computation, which consistently indicated the smallest evapotranspiration, and the energy-balance residual computation, which consistently indicated the largest evapotranspiration. Daily potential evapotranspiration, as computed by the Penman method, and daily evapotranspiration, as computed by the EBBR method, did not seem to correlate with each other at a dry prairie site during late spring and summer; however, the two were correlated with each other at a marsh site during late spring and summer. Evapotranspiration was approximately 57 percent of potential evapotranspiration at the marsh site. The correlation between evapotranspiration and potential evapotranspiration at the marsh site, and the fact that evapotranspiration approached potential evapotranspiration, indicated that the Penman method can be useful for estimating evapotranspiration from marshes in west-central Florida. Annual evapotranspiration estimates were developed for each vegetation type by pooling EBBR and eddy correlation measurements among sites and among the 3 years during which field measurements were made. Three different estimates, which correspond to the three eddy correlation computation methods, were made for each vegetation type. The centric estimates, which were calculated by using the EBBR method with the Bowen ratio obtained from either a mean-gradient system or from eddy correlation measurements, were 1,010 millimeters per year for the dry prairie type, 990 millimeters per year for the marsh vegetation type, 1,060 millimeters per year for the pine flatwood type, and 970 millimeters per year for the cypress swamp type.

Florida↗
USGS1995

Efficiency of a stormwater detention pond in reducing loads of chemical and physical constituents in urban streamflow, Pinellas County, Florida

A multipurpose wet stormwater detention pond in Pinellas Park, Florida was studied to determine its effectiveness in reducing the load of selected water-quality constituents commonly found in urban streamflow. Water-quality samples, and data on streamflow and precipitation were collected at the outflow and principal inflow of detention area 3 on Saint Joe Creek. To compare the constituent loads entering and leaving the detention pond, flows and water quality were monitored simultaneously at the inflow and outflow sites for six storms, and were monitored intermittently during periods of base flow. Lodas od 19 selected chemical and physical constituents were determined. Because all the stormwater entering the detention pond was not measured at the inflow site, computed stormwater inflow loads were adjusted to account for loads from the unmonitored areas. The ratio of storm- water volume measured at the outflow site to stormwater volume measured at the inflow site was used to adjust inflow loads for individual storms. Pond efficiencies for selected water- quality constituents for each of the storms were estimated by dividing the difference in outflow and adjusted inflow loads by the adjusted inflow load. Stormwater loads of the major ions (chloride, calcium and bicarbonate) and dissolved solids at the outflow site exceeded loads at the inflow site, partly as a result of mixing with base flow stored within the pond. However, the detention pond was effective in reducing the stormwater load of such urban-runoff contaminants as metals, nutrients, suspended solids, and biochemical and chemical oxygen demand. Estimated median pond efficiencies for reducing constituent loads ranged from 25 to more than 60 percent for metals, 2 to 52 percent for nutrients, 2 to 52 percent for nutrients, 7 to 11 percent for two measurements of suspended solids, and 16 to 49 percent for the oxygen- consuming substances. The reductions of constituent loads in stormwater are probably a result of dilution with pond water (particularly for smaller storms), adsorption, chemical precipitation, settling, biologic uptake, and oxidation. The establishment of aquatic vegetation midway through the study appears to have increased the efficiency of the pond in reducing loads of urban-runoff contaminants in stormwater. The efficiency of the detention pond in reducing base-flow loads was estimated by comparing base-flow loads at the out- flow site prior to and after construction of the pond. Loads of major ions and dissolved solids in base flow were reduced at median efficiencies ranging from 17 to 35 percent. Urban-runoff con- taminants in base flow were generally reduced at higher efficiencies. Median efficiencies ranged from 38 to 82 percent for metals, 19 to 83 percent for nutrients, 34 to 45 percent for suspended solids, and 43 to 65 for the oxygen-consuming substances. The reductions in loads in base flow are probably a result of adsorption, chemical precipitation, biologic uptake, and settling within the pond. These processes were more effective in reducing base-flow loads after the establishment of aquatic vegetation in the pond.

Water-Resources Investigations Report↗
USGS1983

Magnitude and frequency of flooding on small urban watersheds in the Tampa Bay area, west-central Florida

Hydrologic data collected on nine small urban watersheds in the Tampa Bay area of west-central Florida and a method for estimating peak discharges in the study area are described. The watersheds have mixed land use and range in size from 0.34 to 3.45 square miles. Watershed soils, land use, and storm-drainage system data are described. Urban development ranged from a sparsely populated area with open-ditch storm sewers and 19% impervious area to a completely sewered watershed with 61% impervious cover. The U.S. Geological Survey natural-basin and urban-watershed models were calibrated for the nine watersheds using 5-minute interval rainfall data from the Tampa, Florida, National Weather Service rain gage to simulate annual peak discharge for the period 1906-52. A log-Pearson Type III frequency analysis of the simulated annual maximum discharge was used to determine the 2-, 5-, 10-, 25-, 50-, and 100-year flood discharges for each watershed. Flood discharges were related in a multiple-linear regression to drainage area, channel slope, detention storage area, and an urban-development factor determined by the extent of curb and gutter street drainage and storm-sewer system. The average standard error for the regional relations ranged from + or - 32 to + or - 42%. (USGS)

Florida↗
USGS1982

Comparison of automated satellite systems with conventional systems for hydrologic data collection in west-central Florida

This report provides results of reliability and cost-effective studies of the goes satellite data-collection system used to operate a small hydrologic data network in west-central Florida. The GOES system, in its present state of development, was found to be about as reliable as conventional methods of data collection. Benefits of using the GOES system include some cost and manpower reduction, improved data accuracy, near real-time data availability, and direct computer storage and analysis of data. The GOES system could allow annual manpower reductions of 19 to 23 percent with reduction in cost for some and increase in cost for other single-parameter sites, such as streamflow, rainfall, and ground-water monitoring stations. Manpower reductions of 46 percent or more appear possible for multiple-parameter sites. Implementation of expected improvements in instrumentation and data handling procedures should further reduce costs. (USGS)

Open-File Report↗
USGS1981

Potentiometric surface of the Floridan Aquifer, Southwest Florida Water Management District, May 1981

A May 1981 potentiometric-surface map of the Southwest Florida Water Management District depicts the annual low water-level period. Potentiometric levels decreased 10 to 45 feet between September 1980 and May 1981 in the citrus and farming sections of southern Hillsborough, northern Hardee, southwestern Polk, northwestern DeSoto, and Manatee Counties. Water levels in these areas are widely affected by pumping for irrigation and have the greatest range in fluctuations. Water-level decreases ranged from 0 to 1 feet in coastal, northern, and southern areas of the Water Management District. Water levels in all of the approximate 700 wells measured in May 1981 are lower than May 1980 because of the virtual absence of rainfall in April and May. (USGS)

Open-File Report↗
USGS1981

Ground-water levels in selected well fields and in west-central Florida, May 1981

The water table in the surficial aquifer and the potentiometric surface of the Floridan aquifer in a 1,200-square-mile area in west-central Florida are mapped semi-annually by the U.S. Geological Survey. Maps are based on water levels measured in wells each May to coincide with seasonal low levels and each September to coincide with seasonal high levels. The mapped area shows 14 well fields that supplied 200.7 million gallons to municipalities on May 18, 1981. The water is withdrawn from the Floridan aquifer, the major aquifer in Florida. The effect of localized withdrawal on ground water is shown on the maps as depressions in both the potentiometric and water-table surfaces. Water levels were lower in May 1981 than in May and September 1980. Annual change of water levels ranged from decreases of 19 feet at Sun City well field to less than 1 foot at Eldridge-Wilde well field. (USGS)

Open-File Report↗
USGS1980

Potentiometric surface of the Floridan Aquifer, Southwest Florida Water Management District, September 1980

A September 1980 potentiometric-surface map of the Southwest Florida Water Management District depicts the annual high water-level period. Potentiometric levels rose 1 to 31 feet between May 1980 and September 1980 in the citrus and farming sections of southern Hillsborough, northern Hardee, southwestern Polk, northwestern DeSoto, and Manatee Counties. Water levels in these areas are widely affected by reduced pumping for irrigation and have the greatest range in fluctuations. Generally, potentiometric levels were lower than previous September levels except in Citrus, eastern Levy, and western Marion Counties where levels were 0 to 8 feet higher. (USGS)

Open-File Report↗
USGS1980

Ground-water levels in selected well fields and in west-central Florida, September 1980

The water table in the surficial aquifer and the potentiometric surface of the Floridan aquifer in a 1,200-square-mile area in west-central Florida are mapped semiannually by the U.S. Geological Survey. Maps are based on water levels measured in wells each May to coincide with seasonal low levels and each September to coincide with seasonal high levels. The mapped area shows 14 well fields that supplied 141.8 million gallons to municipalities on September 18, 1980. The water is withdrawn from the Floridan aquifer, the major aquifer in Florida. The effect of localized withdrawal of ground water is shown on the maps as depressions in both the potentiometric and water-table surfaces. Potentiometric levels in the Floridan aquifer were higher in September 1980 than in May 1980 and generally lower than in September 1979. Annual change of water levels ranged from a decrease of 6 feet at Morris Bridge well field to an increase of 2 feet at Eldridge-Wilde well field. (USGS)

Open-File Report↗
USGS1980

Evaluation of remote hydrologic data-acquisition systems, west-central Florida

The study provides an evaluation of the hydrologic applications of a land-line and two satellite data-relay systems operated during 1977-78 in the Southwest Florida Water Management District. These systems were tested to evaluate operational and reliability characteristics. Telephone lines were used to relay data in the land-line system, and the Geostationary Operational Environmental Satellite (GOES) and Land satellite (Landsat) were used in the satellite system. The land-line system was tested for 15 months at a streamflow site. Accurate data were obtained 94% of the time during the test period. Data losses were attributed to telephone-line interference, low-battery voltage, and vandalism. The GOES system was tested at a rainfall site for 17 months. During this period, 79% of the transmissions received from the station were relayed by the GOES system to the U.S. Geological Survey computer, resulting in successful processing of 88% of all possible rainfall observations. On the average, seven data transmissions were completed each day. The Landsat system was tested at a rainfall site for about 17 months and for about 8 months at a streamflow site. During these periods of operation, only about 2% of all data observations for the stations were successfully relayed by the Landsat system to the U.S. Geological Survey computer. An average of about three data transmissions was completed each day for each site. (USGS).

Florida↗
USGS1979

Potentiometric surface of Floridan Aquifer, southwest Florida Water Management District and adjacent areas, May 1979

A May 1979 potentiometric-surface map depicts the annual low water-level period. Potentiometric levels declined 4 to 21 feet between September 1978 and May 1979, in the citrus and farming sections of southern Hillsborough, northern Hardee, southwestern Polk, northwestern DeSoto, and Manatee Counties. Water levels in these areas are widely affected by pumping for irrigation and have the greatest range in fluctuations. Water-level declines ranged from 0 to 6 feet in coastal, northern, and southern areas of the Water Management District. Generally potentiometric levels were higher than previous May levels due to heavy rains in April and May. In parts of Hillsborough, Pasco, and Pinellas Counties, May 1979 potentiometric levels were 18 feet higher than those of September 1978.

Florida↗
USGS1979

Water table in the surficial aquifer and potentiometric surface of the Floridan Aquifer in selected well fields, west-central Florida, May 1979

The water table is the surficial aquifer and the potentiometric surface of the Floridan aquifer in a 1,200-square-mile area in west-central Florida are mapped semiannually by the U.S. Geological Survey. Maps are prepared showing water levels measured in wells each May to coincide with seasonal low levels, and each September to coincide with seasonal high levels. The mapped area shows 16 well fields which supplied 128 million gallons to municipalities on May 15, 1979. The water is withdrawn from the Floridan aquifer, the major aquifer in Florida. Water levels were significantly higher in May 1979 than in May 1978. Heavy rains on May 7 and 8th deluged the well-field areas with 2 to 18 inches of rain. The maximum increase in water levels from May 1978 to May 1979 was more than 8 feet at the Eldridge-Wilde well field. (USGS)

Open-File Report↗
USGS1979

Potentiometric surface of the Floridan Aquifer, Southwest Florida Water Management District, September 1979

A September 1979 potentiometric-surface map of the Southwest Florida Water Management District depicts the annual high water-level period. Potentiometric levels increased 1 to 20 feet between May 1979 and September 1979, in the citrus and farming sections of southern Hillsborough, northern Hardee, southwestern Polk, northwestern DeSoto, and Manatee Counties. Water levels in these areas are widely affected by pumping for irrigation and have the greatest range in fluctuations. Water-level increases ranged from 0 to 7 feet in coastal, northern, and southern areas of the Water Management District. Generally, potentiometric levels were higher than previous September levels due to heavy rains in August and September. (USGS)

Open-File Report↗
USGS1978

Potentiometric surface of the Floridan Aquifer, Southwest Florida Water Management District and adjacent areas, September 1978

A September 1978 potentiometric-surface map depicts the annual high water-level period of the Floridan aquifer in the Southwest Florida Management District. Potentiometric levels increased 10 to 25 feet between May 1978 and September 1978, in the citrus and farming sections of southern Hillsborough, northern Hardee, southwestern Polk and Manatee Counties. These areas are widely affected by pumping for irrigation and have the greatest fluctuations in water-levels between the low and high water-level periods. Water-level rises in coastal, northern and southern areas of the Water Management District ranged from 0 to 10 feet. (Woodard-USGS)

Open-File Report↗