Browsing by Subject "urbanization"

Now showing 1 - 13 of 13

A Biography of Waller Creek, A Case Study in Urbanization and Environment
(The University of Colorado at Boulder, 1995) Foote, Kenneth E.; Molch, Katrin, E.
A Study of Some Effects of Urbanization on Storm Runoff from a Small Watershed
(University of Texas at Austin, 1965-07) Espey, W.H. Jr.; Morgan, C.W.; Masch, F.D.
Application of an electronic analog computer to the evaluation of the effects of urbanization on the runoff characteristics of small watersheds
(1968) Narayana, V.V.D.; Riley, J.P.
In the synthesis of hydrograph characteristics of small urban watersheds, the distribution of the water among the various phases of the runoff process is attempted by the concept of "Equivalent Rural Watershed". The criteria for transforming the urban watershed into an equivalent rural watershed requires that, for a given input into both the models (urban and its equivalent rural watershed), the outputs must be identical. The hydrograph of outflow from an urban watershed is obtained by chronologically deducting the losses due to interception, infiltration and depression storage from precipitation on the equivalent rural watershed and then routing it through the surface and channel storages. This procedure of computing the synthetic outflow hydrograph is accomplished with the analog computer at the Utah Water Research Laboratory, Utah State University at Logan. Testing and verification is done with rainfall and runoff data from the Waller Creek watershed at Austin, Texas. In the verification process, coefficients representing interception, depression storage, and infiltration are determined by trial and error so that the simulated hydrograph is nearly identical to the measured hydrograph of the prototype. The variation in the values of these coefficients from year to year is assumed to be due to the corresponding variations in the characteristics of urbanization defined by the percentage impervious cover and the characteristic impervious length (ratio of the mean length of travel between the center of the impervious area and the discharge measuring point to the maximum length of travel on the watershed). This study attempted to develop the relation between these coefficients and the urbanization parameters.
A Conversation with Tarek M. Shuman: Aging in the year 2000
(Hogg Foundation for Mental Health, 1976) Hogg Foundation for Mental Health
Evaluating the effects of low impact development on Texas A&M University West Campus
(Center for Research in Water Resources, University of Texas at Austin, 2010-12) Rose, Katie; Hodges, Ben R.
The west campus of Texas A&M University is located in the White Creek watershed and has experienced increases in urbanization in recent years. This urbanization has dramatically impacted White Creek, including bank erosion from higher runoff volumes and peak flows. This study uses HEC-HMS and SWMM models to evaluate the effectiveness of low impact development (LID) and best management practices (BMP) in lowering runoff volumes and peak flows on the Texas A&M Campus. The LID techniques evaluated were green roofs, rainwater harvesting and pervious pavements and the BMP evaluated was a detention pond. A new metric, the Hydrologic Footprint Residence, developed by Giacomoni and Zechman (2009) is used for further comparison. HFR incorporates the quantity of flow from a storm with the cross sections of the stream to determine the flood area. This flood area is plotted with respect to time and the area under the curve represents the HFR, in area-time. The LID and BMP technologies were applied to the watershed and evaluated using 77 historical precipitation events. A set of 10 representative storms were used for analysis. In general, the scenario that was the most effective in lowering the peak flow, runoff volume, and HFR of the storm was the combination of rainwater harvesting and pervious pavements. The detention pond was shown to effectively lower the peak flow for larger storms, but does not change the runoff volume of any storm. The LID techniques were shown to be more effective in reducing the impacts of urbanization for small storms. The results also gave insight into the importance of the precipitation intensity and duration. The importance of the Antecedent Moisture Condition of the soil is evaluated in the second part of the study. The AMC was found to have an impact on the peak flows with AMCIII (saturated soil) resulting in the highest peak flow for each storm event and AMCI (dry soil) resulting in lowest peak flow.
Maximizing Benefits of Tourism in Guerrero, Mexico, PRP 93
(LBJ School of Public Affairs, 1991) Stolp, Chandler; Weintraub, Sidney; Glickman, Norman
Methodology for Analyzing Effects of Urbanization on Water Resource Systems
(University of Texas at Austin, 1978-01) Mays, L.W.; Tung, Y.K.
Policymaking in a Redemocratized Brazil Volume 1: Decentralization and Socil Policy, PRP 119
(LBJ School of Public Affairs, 1997) Faria, Vilmar E.; Graham, Lawrence; Wilson, Robert H.
Post-restoration evaluation of urban streams in central Texas
(U.S. Geological Survey / Texas Water Resources Institute, 2006) Meier, Megan D.; Chin, Anne
Study of Some Effects of Urbanization on Storm Runoff From A Small Watershed
(Texas Water Development Board, 1966) Espey, William Howard Jr.; Morgan, Carl W.; Masch, Frank D.
The evaluation of the effects of urbanization on the runoff characteristics of a small watershed is a problem that can be studied by either a short-range or a long- range investigation. Because the long-range type of investigation would require several years for hydrologic data accumulation, it cannot provide any immediate information on the changes in watershed behavior arising as a result of urbanization. A short-range investigation, however, based on synthetic evaluation of present data would provide immediate answers. It is in the realm of this short-range objective that this study of a small urban watershed is directed. This study was made to evaluate the various effects of urbanization on the hydrologic characteristics of a small urban watershed located within Austin, Texas. A linear regression analysis o f data from twenty-four urban and eleven rural watersheds was used to derive equations which would evaluate the past rural conditions and predict future urban conditions for the Waller Creek watershed. The Waller Creek watershed contains two streamflow stations. One i s located at 38th Street and the other at 23rd Street, gaging areas of 2.31 square miles and 4.13 square miles respectively. The watershed above 38th Street is relatively undeveloped when compared to the lower portion of the watershed located between the two stations. The lower portion has extensive residential development and some channel improvement. Results indicate that urban development in the Waller Creek watershed has caused extensive changes in the discharge hydrograph and runoff for the watershed. Prediction of the effects of future development indicate the same trend. The time sequence of the discharge hydrograph will be shortened, the peak discharge will be increased and the unit (in/mi^2) will be increased.
The effects of urbanization on floods in the Austin metropolitan area, Texas
(U.S. Geological Survey, 1986) Veenhuis, Jack E.; Gannett, David G.
The effects of urbanization on flood peaks in streams in the Austin metropolitan area were studied in two separate analyses. In the first analysis, annual peak discharge records at 13 streamflow-gaging sites were used to compute a recorded flood frequency relation for each site. Rainfall and streamflow data for 10 to 20 storms for each of these sites were used to calibrate a rainfall-runoff model in which a 55-year rainfall record was used to simulate 55 annual peak discharges. These simulated discharges also were used to develop a flood-frequency relation at each site. The flood-frequency relations from recorded and generated data were then combined by weighting the recorded flood frequency by the years of record at each site to produce a combined (or weighted) flood frequency at each site. Flood frequencies for all 13 sites were subsequently regressed against basin characteristics at each site to determine possible effects of urbanization. The regression analysis of the combined flood-frequency data for the 13 sites yielded an equation for estimating floods of a given recurrence interval at ungaged sites in the Austin area as a function of the contributing drainage area, the total impervious area percentage, and basin shape. The regression equation estimates that a near fully developed hypothetical drainage basin (impervious area percentage, 45) would have discharges for the 2- and 100-year recurrence interval that are 99 percent and 73 percent greater, respectively, than discharges for those frequencies from a rural drainage basin (impervious percentage, 0). In the second analysis, records at one streamflow-gaging site on Waller Creek were analyzed for changes in rainfall-runoff and flood-frequency relations due to urbanization. Annual peak discharges from 1956 to 1980 and data from a total of 80 storms at the Waller Creek site were analyzed. Both analyses showed increases comparable to those predicted using the equations developed from the 13-station analysis. The last 14 years of record (the near fully developed land-use stage for the Waller Creek analysis) at the two sites on Waller Creek were part of the 13-station analysis. The U.S. Geological Survey, in cooperation with the Texas Department of Water Resources began limited investigations of urban watersheds in Austin in 1954, with the installation of two streamflow-gaging stations and three recording rain gages in the Waller Creek watershed. In 1963, a streamflow gage and three recording rain gages were installed at Wilbarger Creek watershed, a rural area just north of Austin. In cooperation with the City of Austin, the urban study was expanded in 1975 to include additional streamflow and rainfall gaging stations and the collection of surface water-quality data. The number of streamflow-gaging stations increased from 2 to 25 and the number of recording rain gages increased from 3 to 31.
The Effects of Urbanization on Toxic Organics Concentrations in Lake Austin and Town Lake, Texas
(University of Texas at Austin, 1986-06) Wallace, I.E.; Armstrong, N.E.
Water Quality of the Highland Lakes - Determination of the Effect of Urbanization of Impoundment Water Quality
(University of Texas at Austin, 1969-04) Fruh, E.G.; Davis, E.M.