Browsing by Subject "precipitation"

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Analog Computer Simulation of the Runoff Characteristics of an Urban Watershed
(Utah State University, 1969) Narayana, V.V. Dhruva; Riley, J. Paul; Israelsen, Eugene K.
In the syntheses of hydrograph characteristics of small urban watersheds, the distribution of water among the various phases of the runoff process is attempted by the concept of equivalent rural watershed. The urban parameters considered in the study are percentage impervious cover and characteristic impervious length factor. A mathematical model is developed for the equivalent rural watershed with precipitation as input. The hydrograph of outflow is obtained by chronologically deducting the losses due to interception, infiltration, and depression storages from precipitation and then routing through the watershed storage. This mathematical procedure is programmed on an analog computer and is tested with data from the Waller Creek watershed, at Austin, Texas. In the verification process, watershed coefficients representing interception, infiltration, and depression storage are established by trial and error such that the simulated and observed hydrographs are nearly identical with a high statistical correlation. Sensitivity studies indicate the relative influence of the watershed coefficients on the runoff process. The watershed coefficients determined by model verification for each year of study are related to corresponding urban parameters.
Floods of April-June 1957 in Texas and Adjacent States
(U.S. Geological Survey, 1963) Yost, I.D.
The year 1957 in the Southwest was characterized by rainfall that produced a tremendous volume of flood runoff and brought an abrupt end to the severe drought, which had prevailed for several years. The floods of April-June 1957 in Texas and on tributaries to the Red River in Oklahoma and Louisiana were outstanding because of the large extent of the floods and the large volume of runoff produced. All streams in the area, from the Red River to the Rio Grande, were in flood much of the time during this 3-month period. Excluding the Red River and the Rio Grande and considering only the interior streams in Texas, 38 million acre-feet of runoff, adjusted for storage in major reservoirs, was produced over the State during this 3-month period. Peak discharges that exceeded previously known maximums occurred on only a few streams. An outstanding peak flow (45,100 cfs), the maximum since at least 1880, occurred on May 26 on Palo Pinto Creek, a tributary to the Brazos River near Santo, Tex. The stage of May 12 on Sulphur Creek at a site about 3 miles downstream from Lampasas, Tex., was only 1.5 feet lower than that of the flood of 1873. Maximum discharge of record occurred on the Salt Fork Red River and the Washita River, tributaries to the Red River in Oklahoma. This report has been prepared to furnish hydrologic data for detailed planning. Included are general descriptions of the floods, information concerning rainfall, and detailed streamflow records at selected gaging stations throughout areas in Arkansas, Oklahoma, Louisiana, and Texas from the Red River to the Rio Grande.
Hydrologic Data for Urban Studies in the Austin, Texas Metropolitan Area, 1972
(U.S. Geological Survey Water Resources Division, 1974) Wehmeyer, E. E.
Impacts of Fire Emissions and Transport Pathways on the Interannual Variation of CO In the Tropical Upper Troposphere
(2014) Huang, L.; Fu, R.; Jiang, J. H.; Huang, L.; Fu, R.
This study investigates the impacts of fire emission, convection, various climate conditions and transport pathways on the interannual variation of carbon monoxide (CO) in the tropical upper troposphere (UT), by evaluating the field correlation between these fields using multi-satellite observations and principle component analysis, and the transport pathway auto-identification method developed in our previous study. The rotated empirical orthogonal function (REOF) and singular value decomposition (SVD) methods are used to identify the dominant modes of CO interannual variation in the tropical UT and to study the coupled relationship between UT CO and its governing factors. Both REOF and SVD results confirm that Indonesia is the most significant land region that affects the interannual variation of CO in the tropical UT, and El Nino-Southern Oscillation (ENSO) is the dominant climate condition that affects the relationships between surface CO emission, convection and UT CO. In addition, our results also show that the impact of El Nino on the anomalous CO pattern in the tropical UT varies strongly, primarily due to different anomalous emission and convection patterns associated with different El Nino events. In contrast, the anomalous CO pattern in the tropical UT during La Nina period appears to be less variable among different events. Transport pathway analysis suggests that the average CO transported by the "local convection" pathway (Delta COlocal) accounts for the differences of UT CO between different ENSO phases over the tropical continents during biomass burning season. Delta COlocal is generally higher over Indonesia-Australia and lower over South America during El Nino years than during La Nina years. The other pathway ("advection within the lower troposphere followed by convective vertical transport") occurs more frequently over the west-central Pacific during El Nino years than during La Nina years, which may account for the UT CO differences over this region between different ENSO phases.
Predicting Storm-Triggered Landslides
(2011-02) Ren, Diandong; Fu, Rong; Leslie, Lance M.; Dickinson, Robert E.; Dickinson, Robert E.
PREDICTING STORM-TRIGGERED LANDSLIDES An overview of storm-triggered landslides is presented. Then a recently developed and extensively verified landslide modeling system is used to illustrate the importance of two important but presently overlooked mechanisms involved in landslides. The model's adaptive design makes the incorporation of new physical mechanisms convenient. For example, by implementing a land surface scheme that simulates macropore features of fractured sliding material in the draining of surface ponding, it explains. why precipitation intensity is critical in triggering catastrophic landslides. Based on this model, the authors made projections of landslide occurrence in the upcoming 10 years over a region of Southern California, using atmospheric parameters provided by a high-resolution climate model under a viable emission future scenario. Current global coupled ocean atmosphere climate model (CGCM) simulations of precipitation, properly interpreted, provide valuable information to guide studies of storm-triggered landslides. For the area of interest, the authors examine changes in recurrence frequency and spatial distribution of storm-triggered landslides. For some locations, the occurrences of severe landslides (i.e., those with a sliding mass greater than 10(4) m(3)) are expected to increase by similar to 5% by the end of the twenty-first century. The authors also provide a perspective on the ecosystem consequences of an increase in storm-triggered mudslides. For single plants, the morphological features required for defense against extreme events-and those required to maximize growth and reproduction are at odds. Natural selection has resulted in existing plants allocating just enough resources to cope with natural hazards under a naturally varying climate. Consequently, many plant species are not prepared for the expected large changes in extremes caused by anthropogenic climate changes in the present and future centuries.
Watershed Model
(0000-00-00) University of Texas at Austin; Environmental Science Institute