Geology topics

Research about Houston, Texas

Source-linked reports with geographic coverage including Houston, Texas.

At least 37 records · Page 2Linked to original sources

USGS1998

Nutrient loading and selected water-quality and biological characteristics of Dickinson Bayou near Houston, Texas, 1995-97

Data were collected at 10 stations in the Dickinson Bayou watershed near Houston, Texas, from March 1995 through February 1997 to estimate the concentrations, loads, and yields of selected nutrients that enter the bayou; to characterize the effects on nutrient concentrations of flow conditions, seasonality, and land use; and to identify nutrient sources (point or nonpoint) inferred from the occurrence and abundance of algal species in the benthic algal community. These data included rainfall samples, streamflow measurements, stream-water-quality samples, and biological samples, in addition to quality-assurance/quality-control samples. Estimates of loads of selected nutrients for the 106-square-mile watershed during the study were made for point sources and nonpoint sources. Point-source loading data are available only for ammonia nitrogen. Approximately 21.3 pounds per day of ammonia nitrogen is estimated from point sources during the study period. Nonpoint-source loads are estimated for eight nutrient forms: 7.84 pounds per day of dissolved ammonia nitrogen, 5.79 pounds per day of dissolved nitrite nitrogen, 215 pounds per day of dissolved Kjeldahl nitrogen, 350 pounds per day of total Kjeldahl nitrogen, 40.1 pounds per day of dissolved nitrite plus nitrate nitrogen, 67.6 pounds per day of total phosphorus, 46.6 pounds per day of dissolved phosphorus, and 42.8 pounds per day of dissolved orthophosphate. Rainfall-deposition rates also are estimated for comparison with point- and nonpoint-source loads. Deposition rates are 110 pounds per day of dissolved ammonia nitrogen, 120 pounds per day of dissolved nitrate nitrogen, and 15.8 pounds per day of dissolved phosphorus. Statistical tests were used to determine whether there are significant differences between nutrient concentrations during low-flow and during high-flow conditions. For basins with rural/mixed and urban land uses, nutrient concentrations generally are significantly different (greater) during storm events than during low flow, indicating accumulation in the watershed and subsequent washoff of nutrients. However, nutrient concentrations in storm-event samples consisting predominantly of runoff from a pasture are not significantly greater than those in low-flow samples. Statistical tests for seasonality indicate that dissolved ammonia nitrogen is significantly different in at least one season for all land uses (rural/residential, rural/mixed, and pasture) except urban. Concentrations tend to increase in the spring and early summer months, possibly from fertilizer application and subsequent washoff. Constituent-yield data were used to make direct comparisons of the nonpoint-source load contributions from four stations with watersheds of different land use. These comparisons lead to three conclusions: (1) For all nutrient species except orthophosphate, urban land use is the largest nonpoint-source contributor, (2) Kjeldahl nitrogen is the most abundant nutrient species, and (3) organic nitrogen accounts for the major part of the Kjeldahl nitrogen. Algal samples were collected at seven stations and were analyzed for periphyton identification and enumeration, and chlorophyll a and chlorophyll b concentrations. The large relative abundance of soil algae at stations in the middle of the watershed likely indicates the cumulative effects on water quality of agricultural nonpoint sources. Farther downstream near the State Highway 3 bridge, and downstream of three major tributary inflows, the increase in abundance of soil algae to a larger-than-expected level might reflect water-quality influences from predominantly urban nonpoint sources in the drainage basins of the three major tributary inflows. Nutrient concentrations do not appear to limit algal production in the upper (non-tidal) reach of Dickinson Bayou; but nutrient concentrations could have been limiting benthicalgal production in the lower (tidal) reach of the bayou during the time of the synoptic survey. If nitrogen is the limiting resource for algal productivity in the tidal reach of Dickinson Bayou, eutrophication of the system could be (at least partially) mitigated if nonpoint-source nutrient loads into the Bayou were reduced.

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USGS1997

Summary of surface-water hydrologic data for the Houston metropolitan area, Texas, water years 1964-89

The study area, a metropolitan area in southeast Texas about 45 miles north of the Gulf of Mexico, has been undergoing extensive urban development since the 1950s. The Houston Urban Runoff Program was begun by the U.S. Geological Survey in water year 1964 to define the magnitude and frequency of flood peaks, to determine the impact of continuing urban development on surface-water hydrologic responses, and to determine variations in stream water quality for different flow conditions, seasons, and urban development. An extensive data base has been developed. During water years 1964-89, the Houston Urban Runoff Program collected information from a total of 54 U.S. Geological Survey streamflow-gaging stations, 30 U.S. Geological Survey water-quality sampling sites, and 102 rain gages (operated by the U.S. Geological Survey, the National Weather Service, and local agencies). In addition, basin characteristics were developed to aid in understanding the effects of urban development on surface-water hydrologic responses. Surface-water hydrologic data on diskettes describe the 54 U.S. Geological Survey streamflow-gaging stations, list annual peaks (and where available, peaks above an arbitrary base) for 50 streamflow sites, tabulate 1,125 storm hydrographs from 43 sites, and document 102 waterquality parameters determined from 3,242 available samples.

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USGS1995

Summary statistics and graphical comparisons of specific conductance, temperature, and dissolved oxygen data, Buffalo Bayou, Houston, Texas, April 1986-March 1991

Buffalo Bayou is the major stream that drains the Houston, Texas, metropolitan area. The U.S. Geological Survey has provided specific conductance, temperature, and dissolved oxygen data to the City of Houston for three sites along a 7.7-mile reach of Buffalo Bayou since 1986. Summary statistics and graphical comparisons of the data show substantial variability in the properties during 1986-91. Specific conductance ranged from about 100 microsiemens per centimeter at 25 degrees Celsius at each of the three sites to 17,100 microsiemens per centimeter at 25 degrees Celsius at the most downstream site, at the headwaters of the Houston Ship Channel. Water temperatures ranged from 5 to 33 degrees Celsius. Temperatures were very similar at the two upstream sites and slightly warmer at the most downstream site. Dissolved oxygen ranged from zero at the most downstream site to 11.7 milligrams per liter at the most upstream site.

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USGS1993

Ground-water withdrawals, water levels, and ground-water quality in the Houston district, Texas, with emphasis on 1985-89

This report is one in a series of reports prepared by the U.S. Geological Survey, beginning in 1937, on the ground-water resources in the Houston district. The Houston district includes Harris and Galveston Counties, and parts of Brazoria, Fort Bend, Waller, Montgomery, Liberty, and Chambers Counties. The primary emphasis of this report includes ground-water resources information for the district from 1985-89. Some data collected before 1985 and in early 1990 are included to present long-term trends and relations. Ground-water withdrawal in the Houston district decreased from 451 to 419 Mgal/d (million gallons per day) between 1985 and 1989. Public supply used 77 percent of the ground water withdrawn in the district in 1985. From 1985 through 1989, withdrawals for public supply decreased from 349 to 338 Mgal/d, withdrawals for industrial use decreased from 37 to 32 Mgal/d, and withdrawals for irrigation use decreased from 65 to 49 Mgal/d. From 1985 through 1989, ground-water withdrawals decreased from about 197.9 Mgal/d to about 166.9 Mgal/d in the Houston area and increased from about 179.5 Mgal/d to about 180.8 Mgal/d in the Katy area, and remained constant at about 67 Mgal/d in the rest of Harris County. Galveston County ground-water withdrawal decreased from about 6.1 to 4.0 Mgal/d during 1985-89. During 1977-90, water levels in wells completed in the Chicot aquifer in the eastern part of the Houston district rose as much as 160 ft (feet) and declined as much as 80 ft in the western part. During 1985-90, water levels in wells completed in the Chicot aquifer in the western part of the Houston district rose as much as 140 ft, and declined as much as 40 ft in the western part. During 1977-90, water levels in wells completed in the Evangeline aquifer in the southeastern part of the Houston district rose as much as 140 ft and declined as much as 200 ft in the northwestern part. During 1985-90, water levels in wells completed in the Evangeline aquifer in the eastern part of the Houston district rose as much as 40 ft, and declined as much as 140 ft in the northern part. Dissolved-chloride concentrations in water from wells in the Houston district have not changed more than 100 mg/L during 1985-89, except for a decrease at one well in the eastern part of Galveston County. Well KH-65-48-316 yielded water with dissolved-chloride concentration decreasing from 720 mg/L in 1986 to 590 mg/L in 1989.

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USGS1989

Approximate altitude of water levels in wells in the Chicot and Evangeline aquifers in the Houston area, Texas, spring 1989

This report shows the altitudes of water levels in the Chicot and Evangeline aquifers in the Houston metropolitan area, Texas. Of the 425 wells measured, 307 were used to construct the maps of potentiometric surface. The Chicot and Evangeline aquifers are composed of several sand layers, each with a separate potentiometric surface. These maps, however, show a single potentiometric surface which represents the collective water levels for the sand layers comprising each aquifer. Maps showing the altitudes of water levels have been published in many reports on ground-water development in the Houston area, the most recent of which (Gabrysch and others, 1988) presented maps of the altitudes of potentiometric surfaces for 1988.

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USGS1987

Hydrologic data for urban studies in the Houston metropolitan area, Texas, 1984

Hydrologic investigations of urban watersheds in Texas were begun by the U.S. Geological Survey in 1954. Studies are now in progress in the Austin and Houston areas, and have been completed in the Dallas-Fort Worth and San Antonio areas. The U.S. Geological Survey, in cooperation with the city of Houston, began studies in the Houston metropolitan area in 1964. The program was expanded in 1968 to include collection of water-quality data. The objectives of the Houston urban-hydrology study are as follows: To determine, on the basis of historical data and hydrologic analyses, the magnitude and frequency of flood peaks and flood volumes; To determine the effect of urban development on flood peaks and volumes; and To ascertain the variation in water quality for different flow conditions and different seasons. This report, the twenty-first and last scheduled in a series of reports published annually, is primarily applicable to objective 2. The report presents hydrologic data collected in the Houston urban area for the 1984 water year (October 1, 1983 to September 30, 1984). A report by Johnson and Sayre (1973) utilized records collected from 1965 to 1969 to study the effects of urbanization on floods in the Houston area. That report also summarized various basin parameters. A report by Waddell, Massey, and Jennings (1979) presented data on runoff from the Houston area and computed concentrations and loads of selected water-quality constituents discharged to Galveston Bay. The study utilized a variation of the "STORM" model developed by the Hydrologic Engineering Center of the U.S. Army Corps of Engineers. A report prepared by Liscum and Massey (1980) presented a technique for estimating the magnitude and frequency of floods in the Houston area from drainage areas, bank-full conveyance, and percentage of urban development. A definition of terms related to streamflow, water quality, and other hydrologic data, as used in this report, are defined in "U.S. Geological Survey, Water-resources data for Texas, water year 1984, volume 2."

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USGS1987

Effects on water quality due to flood-water detention by Barker and Addicks Reservoirs, Houston, Texas

The Barker and Addicks Reservoirs, located about 16 miles west of Houston, Texas, provide flood-detention storage for storm runoff. Of interest are the water-quality characteristics in the study area and changes in water quality during detention. Study area sampling sites were selected upstream along Buffalo Bayou for Barker Reservoir and on Bear Creek and Langham Creek for Addicks Reservoir, within the reservoirs, near the reservoir outflows, and below the confluence of each reservoir outflow at the streamflow station Buffalo Bayou near Addicks. Flow data were available at all sites except in the reservoirs. Analyses of samples collected during both low flow and storm runoff show that, in general, the waters of the study area were low in mineralization, but the aesthetics of the water was a problem. The inorganic constituents, trace metals, and pesticides rarely exceeded maximum contaminant levels recommended by the U.S. Environmental Protection Agency for public supply using 1976 and 1977 criteria for primary and secondary standards. All species of nutrients, except ammonia nitrogen and phosphorus, almost always were below the recommended maximum contaminant levels. Phosphorus almost always exceeded these levels. Aesthetic problems are evident. Large values of suspended solids, turbidity, and color were common. Small dissolved-oxygen values commonly occurred in the reservoirs. Possible bacterial problems are indicated because coliformbacteria densities exceeded recommended levels in about 25 percent of the samples. The effects of the reservoirs on the water-quality characteristics of storm runoff were analyzed using three approaches. The first approach was a comparison of the discharge-weighted average values of nine selected constituents at each streamflow-gaging station during four storms. Reservoir effects on the quality of runoff detained 1 to 4 days in the two reservoirs were inconsistent. However, the reservoirs consistently had an effect on the water quality of runoff that was detained the longest (more than 8 days). Biochemical oxygen demand, suspended solids, turbidity, color, total nitrogen, and total organic carbon discharge-weighted average values were consistently smaller after flowing through the reservoirs. Dissolved solids and total phosphorus values were consistently larger after flowing through the reservoirs. The second approach was an analysis of the means of the discharge-weighted average values computed for the four hydrologic events using the Student t-test. Statistical results Indicate that reservoir detention significantly reduced suspended solids (the mean decreased from 178 milligrams per liter at the Inflows to 105 milligrams per liter at the outflows) and turbidity (the mean decreased from 119 nephelometrlc turbidity units at the inflows to 66 nephelometric turbidity units at the outflows). The third approach was a comparison at each site of the mean, maximum, and minimum values computed for seven constituents that did not correlate with discharge. These constituents or properties of water were temperature, pH, dissolved oxygen, dissolved oxygen percent saturation, total-coliform bacteria, fecal-conform bacteria, and fecal-streptococci bacteria. The only consistent water-quality changes observed were with the three bacteria groups, which were decreased by flood-water detention.

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USGS1987

Ground-water withdrawals and changes in ground-water levels, ground-water quality, and land-surface subsidence in the Houston district, Texas, 1980-84

During 1980-84, ground-water withdrawals from the Chicot and Evangeline aquifers in the Houston district decreased from 511 million gallons per day to 444 million gallons per day. This 13-percent decrease was due to the increased availability of surface water and a decreased demand for water. The largest decreases in ground-water withdrawals occurred in the Houston area. Ground-water pumpage was 219.2 million gallons per day during 1984 compared to 254.8 million gallons per day during 1980. Decreases in ground-water withdrawals from 1980 through 1984 occurred in most of the other areas in the Houston district (Pasadena, Katy, Baytown-LaPorte, and Texas City). Large decreases in ground-water withdrawals for rice irrigation in the Katy area were offset by increases in ground-water withdrawals for public supply. Hence, in the Katy area, the quantity of ground water withdrawn during 1984, 148.9 million gallons per day, was only slightly less than the 157.5 million gallons per day withdrawn during 1980. Water levels generally rose in the eastern part of the Houston district and declined in the western part from spring 1980 to spring 1985. The rise of water levels in wells in the Chicot and Evangeline aquifers was as much as 80 feet and 60 feet, respectively. The decline of water levels in wells in the Chicot and Evangeline aquifers was as much as 40 feet and 80 feet, respectively. Slight decreases in chloride concentrations in water from the Chicot aquifer occurred in the Alta Loma area between 1980 and 1984. In 1980, chloride concentrations in water from the Chicot aquifer ranged from 250 to 790 milligrams per liter, whereas in 1984, chloride concentrations ranged from 180 to 710 milligrams per liter. Water from one well in the Texas City area had an increase in chloride concentrations from 265 milligrams per liter in 1980 to 300 milligrams per liter in 1984. In water from another well in the Texas City area, chloride concentrations decreased from 760 milligrams per liter in 1980 to 710 milligrams per liter in 1984. The concentrations of chloride and dissolved solids in water from the Evangeline aquifer remained less than 100 milligrams per liter and 500 milligrams per liter during 1980-84. Land-surface subsidence is still evident in the Houston district. Subsidence rates between 1980 and early 1985 in the eastern and southeastern parts of the Houston district were less than during 1975-79. At the Seabrook site, where a monitor measures most of the subsidence, the average compaction rate during 1980 to early 1985 was 0.04 foot per year while during 1975-79, the rate was 0.14 foot per year. However, subsidence rates in the western, southwestern, and northern parts of the Houston district during 1980 to early 1985 increased from the 1975-79 rates. At the Addicks site, the land surface has subsided at a rate of about 0.17 foot per year from 1980 to early 1985. The subsidence rate from 1975 through 1979 at the site was 0.11 foot per year.

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USGS1986

Hydrologic data for urban studies in the Houston metropolitan area, Texas, 1983

Hydro!ogic investigations of urban watersheds in Texas were begun by the U.S. Geological Survey in 1954. Studies are now in progress in the Austin and Houston areas, and have been completed in the Dallas-Fort Worth and San Antonio areas. The U.S. Geological Survey, in cooperation with the city of Houston, began studies in the Houston metropolitan area in 1964. The program was expanded in 1968 to include collection of water-quality data. The objectives of the Houston urban-hydrology study are as follows: To determine, on the basis of historical data and hydrologic analyses, the magnitude and frequency of flood peaks and flood volumes. To determine the effect of urban development on flood peaks and volumes. To ascertain the variation in water quality for different flow conditions and different seasons. This report, the twentieth in a series of reports to be published annually, is primarily applicable to objective No. 2. The report presents hydrologic data collected in the Houston urban area for the 1983 water year (October 1, 1982, to September 30, 1983). A report by Johnson and Sayre (1973) utilized records collected from 1965 to 1969 to study the effects of urbanization on floods in the Houston area. That report also summarized various basin parameters. A report by Waddell, Massey, and Jennings (1979) presented data on runoff from the Houston area and computed concentrations and loads of selected water-quality constituents discharged to Galveston Bay. The study utilized a variation of the "STORM" model developed by the Hydrologic Engineering Center of the U.S. Army Corps of Engineers. A report prepared by Li scum and Massey (1980) presented a technique for estimating the magnitude and frequency of floods in the Houston area from drainage areas, bank-full conveyance, and percentage )f urban development. A definition of terms related to streamflow, water quality, and other hydrologic data, as used in this report, are defined in " U.S. Geological Survey, Water-resources data for Texas, water year 1983, volume 2."

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USGS1985

Hydrologic data for urban studies in the Houston, Texas, metropolitan area, 1981

Hydro! oqic investigations of urban watersheds in Texas were begun by the U.S. Geological Survey in 1954. Studies are now in progress in Austin, and Houston. Studies have been completed in the Dallas-Fort Worth and San Antonio areas. The U.S. Geological Survey, in cooperation with the city of Houston, began studies in the Houston metropolitan area in 1964. The program was expanded in 1968 to include collection of water-quality data. The objectives of the Houston urban-hydrology study are as follows: To determine, on the basis of historical data and hydro!ogic analyses, the magnitude and frequency of flood peaks and flood volumes. To determine the effect of urban development on flood peaks and volumes. To ascertain the variation in water quality for different flow conditions and different seasons. This report, the eighteenth in a series of reports to be published annually, is primarily applicable to objective 2. The report presents hydro!ogic data collected in the Houston urban area for the 1981 water year (October 1, 1980 to September 30, 1981).

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USGS1985

Hydrologic data for urban studies in the Houston, Texas, metropolitan area, 1982

Hydrologic investigations of urban watersheds in Texas were begun by the U.S. Geological Survey in 1954. Studies are now in progress in Austin, and Houston. Studies have been completed in the Dallas-Fort Worth and San Antonio areas. The U.S. Geological Survey, in cooperation with the city of Houston, began studies in the Houston metropolitan area in 1964. The program was expanded in 1968 to include collection of water-quality data. The objectives of the Houston urban-hydrology study are as follows: To determine, on the basis of historical data and hydrologic analyses, the magnitude and frequency of flood peaks and flood volumes. To determine the effect of urban development on flood peaks and volumes. To ascertain the variation in water quality for different flow conditions and different seasons. This report, the nineteenth in a series of reports to be published annually, is primarily applicable to objective 2. The report presents hydrologic data collected in the Houston urban area for the 1982 water year (October 1, 1981 to September 30, 1982). A report by Johnson and Sayre (1973) utilized records collected from 1965 to 1969 to study the effects of urbanization on floods in the Houston area. The report also summarizes various basin parameters. A report by Waddell, Massey, and Jennings (1979) presents data on runoff from the Houston area and computed concentrations and loads of selected water-quality constituents discharged to Galveston Bay. The study utilized a variation of the "STORM" model developed by the Hydrologic Engineering Center of the U.S. Army Corps of Engineers. A report prepared by Li scum and Massey (1980) presents a technique for estimating the magnitude and frequency of floods in the Houston area from drainage areas, bank-full conveyance, and percentage of urban development. A definition of terms related to streamflow, water quality, and other hydrologic data, as used in this report, are defined in "U.S. Geological Survey, Water-resources data for Texas, water year 1982, volume 2." To facilitate the publication and distribution of this report some material has been included that does not conform to the formal publications standards of the U.S. Geological Survey.

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USGS1983

Hydrologic data for urban studies in the Houston, Texas, metropolitan area, 1980

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USGS1983

Faulting arrested by control of ground-water withdrawal in Houston, Texas

More than 86 historically active faults with an aggregate length of 150 miles have been identified within and adjacent to the Houston, Texas, metropolitan area. Although scarps of these faults grow gradually and without causing damaging earthquakes, historical fault offset has cost millions of dollars in damage to houses and other buildings, utilities, and highways that were built on or across the faults. The historical fault activity results from renewed movement along preexisting faults and appears to be caused principally by withdrawal of ground water for municipal, industrial, and agricultural uses in the Houston area. Approximately one-half of the area's water supply is obtained from local ground water. Monitoring by the US Geological Survey of heights of fault scarps indicates that many of the scarps have recently stopped increasing in height. The area where faulting has ceased coincides with the area where ground-water pumping was cut back in the mid-1970s to slow the damage caused by land subsidence along Galveston Bay and the Houston Ship Channel. Thus, it appears that efforts to halt land subsidence in the coastal area have provided the additional benefit of arresting damaging surface faulting. -from Authors

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USGS1982

Hydrologic data for urban studies in the Houston, Texas, metropolitan area, 1979

Hydrologic investigations of urban watersheds in Texas were begun by the U.S. Geological Survey in 1954. Studies are now in progress in Austin, Houston, and San Antonio. The U.S. Geological Survey, in cooperation with the city of Houston, began studies in the Houston metropolitan area in 1964. The program was expanded in 1968 to include collection of water-quality data. The objectives of the Houston urban-hydrology study are as follows: To determine, on the basis of historical data and hydro!ogic analyses, the magnitude and frequency of flood peaks and flood volumes. To determine the effect of urban development on flood peaks and volumes. To ascertain the variation in water quality for different flow conditions and different seasons. This report, the sixteenth in a series of reports to be published annually, is primarily applicable to objective 2. The report presents hydro!ogic data collected in the Houston urban area for the 1979 water year (October 1, 1978 to September 30, 1979). A report by Johnson and Sayre (1973) utilized records collected from 1965 to 1969 to make a study of the effects of urbanization on floods in the Houston area. The report also summarizes various basin parameters. A report by Waddell, Massey, and Jennings (1979) presents data on computed runoff from the Houston area and computed concentrations and loads of selected waterquality constituents combined in the inflow to Galveston Bay. The study utilized a variation of the "STORM" model developed by the Hydro!ogic Engineering Center of the U.S. Army Corps of Engineers. A report prepared by Li scum and Massey (1980) presents a technique for estimating the magnitude and frequency of floods in the Houston area from drainage areas, bank-full conveyance, and percentage of urban development. A definition of terms related to streamflow, water quality, and other hydrologic data, as used in this report, are defined in "U.S. Geological Survey, Water-resources data for Texas, volume 2, 1979." To facilitate the publication and distribution of this report at the earliest feasible time, some material has been included that does not conform to the formal publications standards of the U.S. Geological Survey.

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USGS1981

Approximate altitude of water levels in wells in the Chicot and Evangeline aquifers in the Houston area, Texas, spring 1981

The purpose of this report, which was prepared in cooperation with the City of Houston, the Harris-Galveston Coastal Subsidence District, and the Texas Department of Water Resources, is to show the altitudes of water levels in wells in the Chicot and Evangeline aquifers in the Houston, Texas, metropolitan area. The maps are based on water-level measurements in 1981 in about 500 wells.

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USGS1980

Hydrologic data for urban studies in the Houston, Texas, metropolitan area, 1978

This report contains rainfall and runoff data collected during the 1978 water year for drainage basins in the Houston, Tex., metropolitan area. The information will be useful in determining the extent to which progressive urbanization will affect the yield and mode of occurrence of storm runoff. Rainfall-runoff computations are presented for three storm periods during the 1978 water year. (USGS)

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USGS1980

Technique for estimating the magnitude and frequency of floods in the Houston, Texas, Metropolitan Area

A technique for estimating the magnitude and frequency of floods in the Houston, Texas, metropolitan area was developed by use of a multiple-regression flood-frequency analysis of flow data from unregulated streams in the area. A regression model, relating flood-peak discharge to concurrent rainfall and antecedent soil moisture conditions, was used to simulate 67-year records of annual peak discharges. Flood-frequency characteristics were determined for the simulated annual peaks and for the observed annual peaks at each of 22 gaging stations. Drainage area, bank-full channel conveyance, and percentage of urban development were used as independent variables; and weighted flood-frequency discharges were used as dependent variables in the multiple regression analysis. Relationships applicable to unregulated streams were developed for predicting floods with recurrence intervals of 2, 5, 10, 25, 50, 100, and 500 years. Drainage basins ranged in area from 1.33 to 182 square miles. The percentage of urban development in these basins ranges from 37 to 98.9 percent. The relationships indicate that as a basin changes from a completely natural state to one of complete urbanization, the magnitude of a 2-year peak discharge is increased by a factor of 4.2, the magnitude of a 50-year peak is increased by a factor of 4.9, and the magnitude of a 100-year peak is increased by a factor of 4. 9.

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USGS1979

Faults in parts of north-central and western Houston metropolitan area, Texas

Hundreds of residential, commercial, and industrial structures in the Houston metropolitan area have sustained moderate to severe damage owing to their locations on or near active faults. Paved roads have been offset by faults at hundreds of locations, butted pipelines have been distorted by fault movements, and fault-induced gradient changes in drainage lines have raised concern among flood control engineers. Over 150 faults, many of them moving at rates of 0.5 to 2 cm/yr, have been mapped in the Houston area; the number of faults probably far exceeds this figure. This report includes a map of eight faults, in north-central and western Houston, at a scale useful for land-use planning. Seven of the faults, are known, to be active and have caused considerable damage to structures built on or near them. If the eighth fault is active, it may be of concern to new developments on the west side of Houston. A ninth feature shown on the map is regarded only as a possible fault, as an origin by faulting has not been firmly established. Seismic and drill-hold data for some 40 faults, studied in detail by various investigators have verified connections between scarps at the land surface and growth faults in the shallow subsurface. Some scarps, then, are known to be the surface manifestations of faults that have geologically long histories of movement. The degree to which natural geologic processes contribute to current fault movement, however, is unclear, for some of man’s activities may play a role in faulting as well. Evidence that current rates of fault movement far exceed average prehistoric rates and that most offset of the land surface in the Houston area has occurred only within the last 50 years indirectly suggest that fluid withdrawal may be accelerating or reinitiating movement on pre-existing faults. This conclusion, however, is based only on a coincidence in time between increased fault activity and increased rates of withdrawal of water, oil, and gas from subsurface sediments; no cause-and-effect relationship has been demonstrated. An alternative hypothesis is that natural fault movements are characterized by short—term episodicity and that Houston is experiencing the effects of a brief period of accelerated natural fault movement. Available data from monitored faults are insufficient to weigh the relative importance of natural vs. induced fault movements.

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