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Marshall E. Jennings

Publications and source records attributed to Marshall E. Jennings.

10 recordsLinked to original sources
USGS1996

Floods in Central Texas, December 1991

Record-breaking peak discharges were recorded at eight U.S. Geological Survey (USGS) streamflow-gaging stations in central Texas during December 1991 (fig. 1), and substantial peak discharges also occurred at numerous other stations. Large peak discharges during December are unusual in central Texas. The rainfall causing the flooding began on December 18, with 6-day totals exceeding 10 inches (in.) in the area of heaviest rainfall. This report documents peak discharges and runoff volumes during December 1991. Recurrence intervals were determined for the peak discharges and runoff volumes for 1-, 3-, and 7-day periods. A recurrence interval references the approximate number of years during which a given peak discharge or runoff volumes is expected to be equaled or exceeded only once. A flood of a given recurrence interval is defined on the basis of peak discharge – for example, a 100-year flood is defined as the peak discharge that has a 1-percent chance of being equaled or exceeded in any given year.

Texas↗
USGS1988

Federal microcomputer software for urban hydrology

The purpose of this paper is to describe the development, availability, and general use of selected urban hydrology microcomputer software developed by: U.S. Soil Conservation Service (SCS); U.S. Army Corps of Engineers, Hydrologic Engineering Center (HEC); U.S. Environmental Protection Agency (EPA); and U.S. Geological Survey (USGS). The discussion is limited to software used for design and planning for urban stormwater flows.

Conference Paper↗
USGS1988

Estimation of urban stormwater quality

Two data-based methods for estimating urban stormwater quality have recently been made available - a planning level method developed by the U.S. Environmental Protection Agency (EPA), and a nationwide regression method developed by the U.S. Geological Survey. Each method uses urban stormwater water-quality constituent data collected for the Nationwide Urban Runoff Program (NURP) during 1979-83. The constituents analyzed include 10 chemical constituents - chemical oxygen demand (COD), total suspended solids (TSS), dissolved solids (DS), total nitrogen (TN), total ammonia plus nitrogen (AN), total phosphorus (TP), dissolved phosphorous (DP), total copper (CU), total lead (PB), and total zinc (ZN). The purpose of this report is to briefly compare features of the two estimation methods.

Conference Paper↗
USGS1986

URBAN STORMWATER-QUALITY INVESTIGATIONS BY THE USGS.

U. S. Geological Survey (USGS) urban stormwater investigations, in cooperation with local and Federal agencies, have produced significant national data bases of information and enhanced understanding of urban hydrologic processes. Studies in progress include statistical regionalization of urban stormwater quality, the effects of stormwater detention on water quality, ways of improving instrumentation for urban hydrology studies, and an evaluation and update of urban gaging networks. Studies performed by USGS since 1968, including 12 studies that were in the Environmental Protection Agency Nationwide Urban Runoff Program, are being summarized in a USGS report.

Conference Paper↗
USGS1981

Emergency assessment of Mount St. Helens post-eruption flood hazards, Toutle and Cowlitz rivers, Washington

During several periods of volcanic-ash eruption at Mount St. Helens, Wash., (March 30, May 25-26, May 30-June 2, and June 12-13, 1980) strong winds from the north occurred at high altitudes. As a result, the volcanic ash fell some 50 miles to the south in the Bull Run watershed, the principal water-supply source for the metropolitan area of Portland, Oreg. Water samples collected from three stream sites within the watershed were compared with samples collected during the same season in previous years. No detectable changes were noted in chemical characteristics. Precipitation samples collected immediately after the June 12-13 ash fall ranged in specific conductance from 20 to 41 micromhos per centimeter at 25C and in pH from 4.0 to 4.3 pH units. Stream samples collected during the May-June period ranged in specific conductance from 18 to 28 micromhos per centimeter at 25C and in pH from 6.7 to 7.5 pH units. Volcanic-ash samples were collected and analyzed for particle size, chemical composition, and weight. Significant differences in particle size of ash were found in samples from two separate eruptions. (USGS)

Circular↗
USGS1979

Evaluation of a digital model for estuarine water quality simulation in waste allocation studies

Hydrologic and water-quality data were collected on 4 estuaries in Pasco, Citrus, and Pinellas Counties, Florida, to evaluate modeling results. Current and predicted waste loading of the four estuaries was simulated by use of a two-dimensional steady-state, intertidal-condition model. Concentrations of DO, carbonaceous and nitrogenous BOD, and chloride were simulated as averages over a tidal cycle. General equations for the model are based on the law of conservation of mass. Assumption of steady-state required that water-quality data for calibration be averaged over an appropriate time cycle with respect to volume and cross-section. Diurnal DO fluctuation was determined in 2 estuaries for evaluating the influence of photosynthesis and respiration. The estuary model is best applied by calibrating it for a particular set of observed conditions, and then using this calibrated model for sensitivity analyses without attempting to verify the chosen parameter values against a second set of conditions. Sensitivity analyses included dispersion coefficient , decay rates, photosynthesis, and respiration. (Woodard-USGS)

Water-Resources Investigations Report↗
USGS1979

One-dimensional steady-state stream water-quality model

A computer program, based on a one-dimensional mathematical model which predicts the stream water-quality response characteristics from waste source inputs, is described and documented. Variables predicted include dissolved oxygen, biochemical oxygen demand, nitrogen forms, total and fecal-coliform bacteria, orthophosphate-phosphorus, and various conservative substances. The model is based primarily on the well known Streeter-Phelps oxygen-sag equation. Special options of the program include the capability of handling nonpoint source waste inputs and anoxic conditions. The model formulation is based on a steady-state assumption which requires constant flow rate of waste and stream discharges and associated parameters. To achieve a problem solution, each reach of a stream system is broken into a given number of subreaches, generally defined by locations of waste or tributary inflow points. All waste constituents are assumed to be completely mixed within any cross section.

Water-Resources Investigations Report↗
USGS1979

Use of the STORM model for estimating the quantity and quality of runoff from the metropolitan area of Houston, Texas

The "STORM" model, developed by the U.S. Army Corps of Engineers, was selected from existing models and adapted to use available data to compute runoff from the Houston, Texas, area and to compute the loads and concentrations of biochemicaloxygen demand, dissolved solids, total phosphorus, total organic carbon, total nitrogen, and fecal-coliform bacteria. The water-quality data simulated by the STORM model will be used by the Texas Department of Water Resources to refine and verify a model of the Calveston Bay estuarine system. Discharge and precipitation data for the 1975 water year and all available waterquality analyses were used to calibrate the model for the Buffalo, Whiteoak, Brays, Sims, Hunting, Greens, and Vince Bayous. Data for the 1974 water year were used to verify the model for discharge. After verification, the calibrations were adjusted to balance the difference between the 1974 and 1975 error predictions for discharge. The adjusted model was used with records of precipitation and evaporation to simulate a 20-vear record of the quantity and quality of runoff from the modeled area.

Texas↗
USGS1977

Routing of stormwater flows through storm drains

Storm-drain flow-routing methods based on kinematic-wave routing and storage-routing methods are compared with the MLSR (multiple-linearization storm-drain routing) method for hypothetical circular pipe problems. The MLSR method, based on a diffusion-wave routing concept, is shown to give very good results without incurring the numerical solution or damping problems of other methods.

Journal of Research of the U.S. Geological Survey↗