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M. A. Lopez

Publications and source records attributed to M. A. Lopez.

11 recordsLinked to original sources
USGS1993

Evapotranspiration from areas of native vegetation in west-central Florida

A study was made to examine the suitability of three different micrometeorological methods for estimating evapotranspiration from selected areas of native vegetation in west-central Florida and to estimate annual evapotranspiration from those areas. Evapotranspiration was estimated using the energy- balance Bowen ratio and eddy correlation methods. Potential evapotranspiration was computed using the Penman equation. The energy-balance Bowen ratio method was used to estimate diurnal evapotrans- piration at unforested sites and yielded reasonable results; however, measurements indicated that the magnitudes of air temperature and vapor-pressure gradients above the forested sites were too small to obtain reliable evapotranspiration measurements with the energy balance Bowen ratio system. Analysis of the surface energy-balance indicated that sensible and latent heat fluxes computed using standard eddy correlation computation methods did not adequately account for available energy. Eddy correlation data were combined with the equation for the surface energy balance to yield two additional estimates of evapotranspiration. Daily potential evapotranspiration and evapotranspira- tion estimated using the energy-balance Bowen ratio method were not correlated at a unforested, dry prairie site, but they were correlated at a marsh site. Estimates of annual evapotranspiration for sites within the four vegetation types, which were based on energy-balance Bowen ratio and eddy correlation measurements, were 1,010 millimeters for dry prairie sites, 990 millimeters for marsh sites, 1,060 millimeters for pine flatwood sites, and 970 millimeters for a cypress swamp site.

Open-File Report↗
USGS1989

Trend analysis of Lake Parker stage and relation to various hydrologic factors, 1950-86, Lakeland, Florida

Kendall tau test and regression analysis were used to determine if statistically significant long-term trends exist for Lake Parker, Florida stage data or for four other area lakes, four groundwater sites, four rainfall sites, Lakeland public-supply pumpage, and pan evaporation. A 10% significance level was used for criterion of an existing trend. Findings were consistent between the two analytical methods. There were no long-term trends indicated for seasonal or annual stage data at Lake Parker. Statistically significant Kendall tau slope estimators were detected for pan evaporation (+0.45 in/yr), Lakeland well-field pumpage (+0.56 million gal/day/yr), and one groundwater site (+0.48 ft/year). Decreasing trends were indicated for three other lakes (-0.03 to -0.27 ft/year) and one groundwater site (-0.25 ft/year). Kendall tau tests of four annual rainfall records indicated no long-term trends. Change in Lake Parker stage from November to May was related by multiple linear regression to change in groundwater level, rainfall, and pumpage for the same time period. The regression coefficient of determination was 0.90, and the standard error was 0.24 ft. Monthly change in lake stage for November through May was related to evaporation, rainfall, and groundwater levels with a coefficient of determination of 0.67 and a standard error of 0.14 ft. (USGS)

Water-Resources Investigations Report↗
USGS1984

Water-quality characteristics of urban runoff and estimates of annual loads in the Tampa Bay area, Florida, 1975-80

Rainfall, runoff, and water quality data were collected at nine urban watersheds in the Tampa Bay area from 1975 to 1980. Watershed drainage area ranged from 0.34 to 0.45 sq mi. Land use was mixed. Development ranged from a mostly residential watershed with a 19% impervious surface, to a commercial-residential watershed with a 61% impervious surface. Average biochemical oxygen demand concentrations of base flow at two sites and of stormwater runoff at five sites exceeded treated sewage effluent standards. Average coliform concentrations of stormwater runoff at all sites were several orders of magnitude greater than standards for Florida Class III receiving water (for recreation or propagation and management of fish and wildlife). Average concentrations of lead and zinc in stormwater runoff were consistently higher than Class III standards. Stormwater-runoff loads and base-flow concentrations of biochemical oxygen demand, chemical oxygen demand, total nitrogen, total organic nitrogen, total phosphorus, and lead were related to runoff volume, land use, urban development, and antecedent daily rainfall by multiple linear regression. Stormwater-runoff volume was related to pervious area, hydraulically connected impervious surfaces, storm rainfall, and soil-infiltration index. Base-flow daily discharge was related to drainage area and antecedent daily rainfall. The flow regression equations of this report were used to compute 1979 water-year loads of biochemical oxygen demand, chemical oxygen demand, total nitrogen, total organic nitrogen, total phosphorus , and total lead for the nine Tampa Bay area urban watersheds. (Lantz-PTT)

Water-Resources Investigations Report↗
USGS1984

Regional flood relations for unregulated lakes in west-central Florida

Regional lake flood altitude in the Southwest Florida Water Management District for 2- to 500-year recurrence intervals was estimated by multiple linear-regression analysis. The average lake altitude was used as a reference above which flood volumes are related to lake geometry, watershed characteristics, and rainfall. Average altitude at surface-outflow lakes is related to the altitude of the lake surface shown on topographic maps, lake-outlet altitude, and annual rainfall. Average altitude at closed-basin lakes is related to the altitude of the lake surface shown on topographic maps. Flood volume above average altitude for surface-outflow lakes is related to lake geometry, watershed characteristics, and rainfall. The average standard error of estimate for regional relations of surface-outflow lakes ranges from 29 to 54 percent in the Central Lake District and from 50 to 58 percent in the Ocala Uplift District. The average standard error of estimate for regional relations of closed-basin lakes ranges from 22 to 40 percent. Regional relations for average altitude and flood volume above average altitude are used to weight station flood-altitude data. Tables comparing station, regional, and weighted lake flood altitudes are shown for 47 lakes used in the analysis. (USGS)

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↗
USGS1975

Techniques for water demand analysis and forecasting: Puerto Rico, a case study

The rapid economic growth of the Commonwealth-of Puerto Rico since 1947 has brought public pressure on Government agencies for rapid development of public water supply and waste treatment facilities. Since 1945 the Puerto Rico Aqueduct and Sewer Authority has had the responsibility for planning, developing and operating water supply and waste treatment facilities on a municipal basis. The purpose of this study was to develop operational techniques whereby a planning agency, such as the Puerto Rico Aqueduct and Sewer Authority, could project the temporal and spatial distribution of .future water demands. This report is part of a 2-year cooperative study between the U.S. Geological Survey and the Environmental Quality Board of the Commonwealth of Puerto Rico, for the development of systems analysis techniques for use in water resources planning. While the Commonwealth was assisted in the development of techniques to facilitate ongoing planning, the U.S. Geological Survey attempted to gain insights in order to better interface its data collection efforts with the planning process. The report reviews the institutional structure associated with water resources planning for the Commonwealth. A brief description of alternative water demand forecasting procedures is presented and specific techniques and analyses of Puerto Rico demand data are discussed. Water demand models for a specific area of Puerto Rico are then developed. These models provide a framework for making several sets of water demand forecasts based on alternative economic and demographic assumptions. In the second part of this report, the historical impact of water resources investment on regional economic development is analyzed and related to water demand .forecasting. Conclusions and future data needs are in the last section.

Open-File Report↗
USGS1967

Climate and streamflow of Puerto Rico

The presently available data on streamflow, runoff rainfall, and temperature of Puerto Rico are evaluated, although the period of record is very short, with a view to contributing to the knowledge of hydrology of tropical islands. The average annual streamflow in Puerto Rico is 45 percent of the annual rainfall, or 15 percent more than in the eastern piedmont of the U.S. where it is 30 percent. Climate is assumed to be responsible for this difference as well as for the differences of the flows of Puerto Rican streams which vary from 15 to 85 percent of the annual rainfall. Variations in the climate of Puerto Rico are shown by Thornthwaite's climatic index on a map of the island, and the variations of the streamflow to rainfall ratios of Puerto Rican streams are shown to be related to Thornthwaite's climatic index.

Caribbean Journal of Science↗