Geology topics
M. A. Lopez
Publications and source records attributed to M. A. Lopez.
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)
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)
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.
Floods in the Ponce area, Puerto Rico
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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.