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R. G. Brown

Publications and source records attributed to R. G. Brown.

9 recordsLinked to original sources
USGS2007

Effects of Precipitation and Land Use on Storm Runoff

Storm-runoff quantity and quality were studied in three watersheds located near St. Paul in Ramsey County, Minnesota, from April 15 through September 15 of 1984, 1985, and 1986 to qualitatively determine the effects of precipitation and selected land uses on storm runoff. In respect to precipitation effects, differences in storm-runoff quantity between years in an urban watershed that lacks wetlands appear to be related to the average storm size (amount of precipitation) during the study period of each year. In contrast, the differences in storm-runoff quantity from watersheds that contain wetlands appear to be related to total precipitation during study period of each year. In respect to land use, the differences in storm-runoff quantity appear to be related to the amounts of impervious and wetland area. The watershed that contains the largest amount of impervious area and smallest amount of wetland area has the largest amount of storm runoff.

Water Resources Bulletin↗
USGS1985

Ground-water and surface-water interactions in Minnesota and Wisconsin wetlands

The interaction between ground water and surface water in wetlands is complex and depends on the hydrologic setting of the particular wetland. Hydrologic characteristics have been used in Wisconsin to classify wetlands into four categories; surface-waterdepression wetlands, surface-water-slope wetlands, ground-waterdepression wetlands, and ground-water-slope wetlands, as described by Novitzki (1978). The degree of ground- and surface-water interactions differs between the four categories.

Minnesota, Wisconsin↗
USGS1985

Runoff and chemical loading in small watersheds in the Twin Cities Metropolitan Area, Minnesota

Flow, rainfall, and water-quality data were collected during 1980 for 15 to 30 rainfall and snowmelt events on 6 rural and 11 urban watersheds in the Twin Cities Metropolitan Area. Event or daily flow and load models (for seven constituents) were developed and used with runoff and rainfall data for 1963-80 to compute 2-year frequency annual and seasonal flows and loads for each watershed. In models of storm-sewered watersheds, total storm rainfall proved to be the most significant factor controlling runoff and loads. Depending on the watershed type, antecedent soil-moisture indices and rainfall intensity also were important factors in estimating runoff. Annual runoff from storm-sewered watersheds averaged about 27 percent of annual precipitation, ranging from 13 to 57 percent. Runoff in urban main-stem streams ranged from 13 to 20 percent and was related to the percent of urbanization in the watershed. Annual runoff in rural watersheds ranged from 6 to 20 percent of annual precipitation. Runoff responses were highest in the snowmelt season for all watersheds and declined through the rest of the year. Rural watersheds showed a considerable decrease in runoff response during late summer and fall. Urban-watershed response from season to season was more consistent than rural watersheds because of the impervious area and storm sewers in urban watersheds. (USGS)

Minneosta↗
USGS1985

Hydrologic factors affecting lake-level fluctuations in Big Marine Lake, Washington County, Minnesota

A study by the U.S. Geological Survey from 1981 through 1984, in cooperation with the Carnelian-Marine Watershed District and the Minnesota Department of Natural Resources, investigated the causes of large lake-level fluctuations at Big Marine Lake. Historic records document that Big Marine Lake has changed substantially in surface area during the period 1847 through 1983; the maximum lake-surface area was 2,300 acres in 1847, and the minimum lake-surface area was 890 acres in 1938. A change in lake level of about 11 feet caused these changes in surface area. Serious flooding of lake-shore properties has occurred in recent years because residential development commonly took place during periods of relatively low-lake level during the 1950's and 1960's. Evaporation from the lake was estimated to be approximately equal to incident precipitation on the lake surface on an annual basis. Big Marine Lake does not have a surface-water inlet, and the outlet from the lake is at an elevation well above the stage at which lake-shore property is flooded. Hydrogeologic and geochemical data collected during the study show that (1) fluctuation of water levels at Big Marine Lake is controlled primarily by ground-water discharge to and seepage from the lake, (2) water in the drift aquifer and water in the lake are chemically similar, and (3) changes in the potentiometric surface of the bedrock aquifer have minor effects on changes in lake level. Long-term trends in cumulative departure from mean annual precipitation suggest that recharge to the drift aquifer in the area has been increasing since the 1940's. The increase in precipitation and recharge corresponds to the observed rise in lake level since 1965 when regular lake-level measurements began. Fluctuations in lake level in the future will depend on changes in recharge to the drift and bedrock aquifers, which is directly related to changes in long-term precipitation patterns.

Minnesota↗
USGS1984

Effects of an urban wetland on sediment and nutrient loads in runoff

An urban wetland in the Minneapolis-St. Paul Metropolitan Area was found to retain sediment and nutrient loads in runoff routed through the wetland. Sediment and nutrient loads in runoff were measured during 1982 at the inlet and outlet of the 6.4-bectare urban wetland. Comparison of annual loads entering and leaving the wetland showed that retention of incoming loads in the wetland was 97 percent of nonvolatile suspended solids, 76 percent of volatile suspended solids, 48 percent of total phosphorus, 4 percent of dissolved phosphorus, 3 percent of dissolved nitrite plus nitrate nitrogen, 1 percent of total ammonia nitrogen, and 47 percent of total organic nitrogen. Flow volume was increased on an annual average basis by 5 percent between the wetland inlet and oulet. Most retention of sediment and nutrient loads occurred between late April and mid-July. Retention of sediment and nutrient loads in the wetland was associated with sedimentation processes. Dissolved nutrients generally were not retained in the wetland because the residence time of water passing through was not long enough for removal by biological processes. Effectiveness of the wetland in retaining sediment and nutrient loads in runoff varies annually. Long-term and short-term impacts of the retention of sediment and nutrients in the wetland on wetland flora and fauna are unknown.

Minnesota↗
USGS1983

Streamflow and water-quality data for lake and wetland inflows and outflows in the Twin Cities metropolitan area, Minnesota, 1981-82

A study of runoff to selected lakes was done in the Twin Cities metropolitan area from July 1981 to December 1982. The purpose of the study was to determine differences in nutrient-loading characteristics for lakes with and without wetlands and settling ponds. The study also quantified nutrient loading to lakes on a storm, seasonal, and annual basis, complementing an inlake water-quality study of these lakes done by the Metropolitan Council. Discharge and water-quality data were collected periodically during 1981 and continuously during 1982 at 22 sites located in seven lake watersheds Bryant Lake, Lake Elmo, Fish Lake, Lake George, Lake Riley, Spring Lake, and Square Lake. Basin characteristics and land use were determined for each watershed. Recording instruments provided continuous discharge records at 14 sites and continuous rainfall records at six sites. Automatic water-quality samplers were used at lake inlets. The automatic samplers collected samples at 1- to 2-hour intervals during storms. Lake-outlet samples were collected manually on a weekly basis during flow. Samples were analyzed for suspended solids and nutrients. Atmospheric-input data were collected at eight sites from September 23 to November 1, 1982. Discharge and water-quality data were used to calculate storm, seasonal, and annual loads of total suspended solids, volatile suspended solids, total phosphorus, dissolved phosphorus, nitrite-plus-nitrate nitrogen, ammonia nitrogen, and ammonia-plus-organic nitrogen. All data collected during the study are documented in tables and graphs that contain (1) watershed characteristics and land use; (2) storm concentrations; (3) storm, seasonal, and annual loads; (4) storm hydrographs; (5) atmospheric-input concentrations and loads; (6) storm, seasonal, and annual precipitation totals; and (7) results of quality-assurance tests.

Minnesota↗