STORM WATER RUNOFF QUALITY FROM THREE LAND-USE AREAS IN SOUTH FLORIDA1

ABSTRACT: Storm water runoff studies of three small basins (20, 40, and 58 acres) in the Fort Lauderdale area of Florida were conducted by the U.S. Geological Survey in 1974–78. The basins were homogeneously developed with land uses being: commercial, single family residential, and high traffic volume highway. Synchronized data were collected for rainfall, storm water discharge, storm water quality, and bulk precipitation (rainfall plus dry fallout) quality. Analysis of the storm water discharge data showed that most runoff was from impervious areas hydraulically connected to drain inlets. Regression analyses of the storm water discharge and water quality data indicated that storm loads from the single family residential area correlated strongly with peak discharge and length of antecedent dry periods. Storm loads from the highway area correlated strongly with rainfall and less strongly with peak discharge and antecedent dry periods. Storm loads from the commercial area correlated strongly with peak discharge and rainfall, and less strongly with antecedent dry periods. On a unit area basis, the single family residential area yielded the largest loads of nitrogen, phosphorus, and dissolved solids. The commercial area yielded the largest loads of lead, zinc, and chemical oxygen demand. Yields of carbon were about the same for the three areas. Constituent loadings derived directly from the atmosphere were estimated on the basis of bulk precipitation samples and compared with storm runoff loads from the highway and commercial areas.     

WATER QUALITY TRAP EFFICIENCY OF STORM WATER MANAGEMENT BASINS1

ABSTRACT: While the quality of rivers has received much attention, the degradation of small streams in upland areas of watersheds has only recently been recognized as a major problem. A major cause of the problem is increases in nonpoint source pollution that accompany urban expansion. A case study is used to examine the potential for storm water detention as a means of controlling water quality in streams of small watersheds. The storm water management basin, which is frequently used to control increases in discharge rates, can also be used to reduce the level of pollutants in inflow to receiving streams. Data collected on a 148-acre site in Maryland shows that a detention basin can trap as much as 98 percent of the pollutant in the inflow. For the 11 water quality parameters, most showed reductions of at least 60 percent, depending on storm characteristics.     

CHEMICAL CONSTITUENTS IN STORM FLOW VS. DRY WEATHER DISCHARGES IN CALIFORNIA STORM WATER CONVEYANCES1

ABSTRACT: This research evaluated concentration data for selected water quality parameters in selected California urban separate storm sewer systems during storm event discharges and during dry weather conditions. We used existing monitoring data from multiple regulatory agencies and municipalities originally collected for compliance or local characterization, which allowed systematic assessment of seasonal patterns over a wide region. Long term mean concentration for most parameters in most streams was higher during storm discharges than during dry weather flows to at least 95 percent confidence in 20 of 45 comparative evaluations, and lower statistical confidence in 22 other comparisons. Some regional differences emerged: in four evaluated streams in the San Francisco Bay Area, total concentration of lead, copper and zinc were lower during dry weather than during storm flows to at least 99.9 percent confidence, with only one exception; while the other four evaluated California streams showed the same tendency, but to much lower statistical confidence.     

WATER QUALITY CHARACTERISTICS OF STORM WATER FROM MAJOR LAND USES IN SOUTH FLORIDA1

ABSTRACT: Starting in 1998, a study was conducted to characterize storm water quality from predominant land use types in a coastal watershed along the south central coast of Florida, namely citrus, pasture, urban, natural wetland, row crop, dairy, and golf courses. Sixty‐three sampling sites were located at strategic points on drainage conveyances for each of seven specific land use areas. Runoff samples were collected following storm events that met defined rainfall criteria for a period of 30 months. Nitrogen (N), phosphorus (P), heavy metals, pesticides, and other water quality parameters were determined, and the results were analyzed to compare and characterize land uses as relative sources for these constituents in runoff. Results showed that runoff from most land use types had low dissolved oxygen concentration and that sediment and nutrient concentrations were closely related to land use, particularly to the amount of fertilizer applied in each land use. Among the eight heavy metals tested, copper was the most frequently detected and was mostly associated with runoff from citrus and golf course land uses. High levels of arsenic were also detected in golf course runoff. The most frequently detected pesticide was simazine from citrus. The information and methodologies presented may facilitate pollution source characterization and ecological restoration efforts.     

DUAL PURPOSE DETENTION BASINS IN STORM WATER MANAGEMENT1

Storm water management contributes to flood hazard mitigation; but new approaches now being developed consider also the reduction in particulate pollution and stream erosion. Such approaches involve retardation of storm runoff, or detention programs of some kind, and detention basins are usually required if large storms are to be controlled. The usual concept is that future storms occurring after development should have no more adverse effect than similar storms would have had before development; but a number of different criteria are being used. If control of storms of different sizes is required, only a small amount of additional capacity is required to obtain retention of particulate pollution in the same basin. In at least three different parts of the country, such dual purpose detention basins are being required of developers. In such programs the developers bear the cost, the governmental contributions are not involved.     

NITROGEN AND PHOSPHORUS IN WATER AS RELATED TO ENVIRONMENTAL SEVI'ING IN NEBRASKA1

ABSTRACT: Spatial distributions of nitrogen and phosphorus in water were related to environmental setting as part of a regional water-quality assessment of the Central Nebraska Basins. The environmental settings (Sandhills, Loess Hills, Glaciated Area, and Platte Valley) were characterized by different concentrations of nitrogen and phosphorus in ground water and stream water. Statistically significant differences in nitrate concentrations in both ground-water and stream-water samples were related to regional distributions of cropland and rangeland. Nitrate concentrations were larger, especially in shallow ground water, in environmental settings dominated by cropland and associated fertilizer use than in settings dominated by rangeland. Similarly, total-nitrogen and nitrate concentrations were relatively large in selected streams draining primarily cropland. Comparative concentrations of phosphorus in stream water on the basis of environmental setting were similar to those of nitrogen, although the largest phosphorus concentrations probably relate to wastewater discharge into small streams. Nitrogen and phosphorus concentrations in much of the Platte River apparently reflected the quality of water entering the study unit from upstream and limited base-flow contributions from within the Platte Valley itself.     

PRELIMINARY OBSERVATIONS ON WATER QUALITY OF STORM RUNOFF FROM FOUR SELECTED RESIDENTIAL ROOFS1

ABSTRACT: Storm runoff from four characteristic types of residential roofs and incident rainwater were monitored for 47 storm events over a six-month period at Nacogdoches, Texas, to study water quality conditions for 20 element and four chemical variables. The total element concentration in storm runoff from each roof type was greater than that of rainwater in the open. Differences in element concentrations in storm runoff among the four roof types were statistically significant (α≤ 0.05) with the differences for the wood shingle roof being the greatest and that for terra cotta clay roof being the least. The median concentrations of four element variables exceeded the Texas surface water quality standards, while 12 variables exceeded the standards at least one time in all samples collected. Zinc concentrations violated the Standard ranging from 85.7 percent of the samples for the wood shingle roof to 66.0 percent for the composite shingle, the greatest exceedances of all 24 variables studied. Storm characteristics and gutter maintenance level had some effects on these water quality conditions. The study suggested that roof types can be important to water pollution management programs. More detailed studies on roof water quality in major municipalities are required.     

PERSPECTIVES FROM THREE YEARS EXPERIENCE OF REGIONAL WATER SERVICES IN THAMES WATER AUTHORITY1

ABSTRACT: Thames Water is one of ten regional Water Authorities established in 1974 to manage all water services in England and Wales. This paper looks back at water reorganization and reviews the achievements and highlights of the last three years. Constitutionally, Water authorities are a combination of a nationalized industry and local authority. This has advantages and disadvantages. Freedom of action, particularly in financial matters, is constrained by Government and official agencies. A severe pollution of the upper Thames and the drought of 1976 tested Thames Water's ability to deal with emergencies. Thames Water does not have an operational monopoly. Private Water Companies supply one third of the water demand and local authorities manage nearly all the sewers. But Thames Water's control over planning and investment ensures that the river basin is managed in a coordinated fashion. Tariff structure changes have led the Authority to bill all its consumers direct. The Thames is a small but intensively used river and vigilance is needed to maintain water quality. Thames Water is proud of the restoration of the tidal Thames from a typical grossly polluted metropolitan estuary to its present excellent condition. The British Government intends to establish a national water industry strategic planning organization but at the same time they affirm that there can be no departure from the principle of integrated river basin management.     

KNOWLEDGE UTILIZATION IN WATER MANAGEMENT IN THE NETHERLANDS RELATED TO DESICCATION1

ABSTRACT: The use of scientific knowledge in environmental policy making is an important topic. However, the relation between knowledge producers and policy makers is not a straightforward producer-user relationship. The development of a national desiccation policy in the Netherlands and the implementation of desiccation plans in local situations are used as a case study to investigate the knowledge policy relationship. Three theoretical explanations were used to analyze this case: a difference between the cultures of producers and users; a different rationality of the policy making and research processes; and processes of social construction of problem definitions which imply that different knowledge stocks are used depending on the framing of the policy problem. Emergence of the policy issue at the national level is demonstrated to develop in close interaction between knowledge producers and policy makers, while the interactions at the local level were more based on integration of expert knowledge through personal expertise and closely tied to the development of management plans. This case study thus reveals a difference between general knowledge supporting measures at the national policy level and the way in which specific knowledge is applied in local cases. Therefore more attention should be paid to the translation of policy problems from rather high levels of political authority to the conceptualization at lower management levels. A final conclusion is that knowledge use in Dutch desiccation policy can be understood by pointing to multiple theoretical perspectives. The rational actor model and a construc-tivist perspective turned out to be especially useful in explaining the different ways knowledge was used at the national and the local level.     

A STORM WATER MANAGEMENT MODEL FOR URBAN AREAS IN KUWAIT1

ABSTRACT: A comprehensive study was conducted to implement the Storm Water Management Model (SWMM) for urban areas in Kuwait. The updated version of the model designed to run on an IBM Personal Computer and compatibles (PCSWMM3.2C) was utilized. The study revealed that urban runoff simulation in arid areas by the SWMM model is a powerful and efficient tool in designing drainage systems and as such, a viable replacement of the commonly used rational method. It was found that only the streets and paved areas that are hydraulically connected to the drainage system contribute to runoff. Fine and coarse discretization approaches were used in the study. The difference between the hydrographs simulated by the two approaches were relatively small. The performance of the existing drainage system and the accuracy of the design method used were tested using a 25-year storm. The result of the simulation revealed that the storm sewers were oversized by factors ranging from 1.2 to 3.6. The SWMM model was used to estimate the storm water runoff volume collected from all urbanized areas in Kuwait City. The annual expected harvested runoff water was found to be significant; however, the quality of runoff water needs to be assessed before a decision is made on its reuse.     

EVALUATION OF HYDROLOGIC BENEFITS OF INFILTRATION BASED URBAN STORM WATER MANAGEMENT1

ABSTRACT: As watersheds are urbanized, their surfaces are made less pervious and more channelized, which reduces infiltration and speeds up the removal of excess runoff. Traditional storm water management seeks to remove runoff as quickly as possible, gathering excess runoff in detention basins for peak reduction where necessary. In contrast, more recently developed “low impact” alternatives manage rainfall where it falls, through a combination of enhancing infiltration properties of pervious areas and rerouting impervious runoff across pervious areas to allow an opportunity for infiltration. In this paper, we investigate the potential for reducing the hydrologic impacts of urbanization by using infiltration based, low impact storm water management. We describe a group of preliminary experiments using relatively simple engineering tools to compare three basic scenarios of development: an undeveloped landscape; a fully developed landscape using traditional, high impact storm water management; and a fully developed landscape using infiltration based, low impact design. Based on these experiments, it appears that by manipulating the layout of urbanized landscapes, it is possible to reduce impacts on hydrology relative to traditional, fully connected storm water systems. However, the amount of reduction in impact is sensitive to both rainfall event size and soil texture, with greatest reductions being possible for small, relatively frequent rainfall events and more pervious soil textures. Thus, low impact techniques appear to provide a valuable tool for reducing runoff for the events that see the greatest relative increases from urbanization: those generated by the small, relatively frequent rainfall events that are small enough to produce little or no runoff from pervious surfaces, but produce runoff from impervious areas. However, it is clear that there still needs to be measures in place for flood management for larger, more intense, and relatively rarer storm events, which are capable of producing significant runoff even for undeveloped basins.     

WATER QUALITY PATTERNS DURING A STORM ON A MALL PARKING LOT1

ABSTRACT: Intensive temporal sampling of rainfall, surface runoff and subsurface drainage, and stream flow upstream and downstream of a suburban mall parking lot yielded expected patterns in time and space. Variations in temperature and conductivity showed strong dilution effects, while patterns of nine elemental concentrations in surface runoff showed a flushing effect early in the storm, following by dilution. Heavy nitrate loads in surface runoff were apparently from rainfall, not surficial sources. For the magnitude of storm studied and the existing study site, local impact on stream flow and water quality, like the run-off itself, is rather ephemeral, and dissipates after about five hours.     

EVALUATING THE ACCURACY OF RAINFALL CATCH BY THREE DIFFERENT GAGES1

ABSTRACT: A U.S. standard gage, a weighing-type recording gage, a standard gage fitted with an Alter windshield, and a pit gage were installed to evaluate the accuracy and wind effects on rainfall catch. The study was conducted at the Stephen F. Austin Experimental Forest, about 20 km SW of Nacogdoches, Texas. A recording anemometer was also installed at a height corresponding to the standard gage orifice. Based on data from 67 storms collected over a one-year period (July 1995-August 1996), all three conventional gages consistently caught less rainfall than the reference pit gage with an average percent deficiency greater than 10 percent. However, the recording gage caught 2.7 percent less and the shielded gage caught 1 percent more than the standard gage—differences less than those reported elsewhere. The deficiencies were highly correlated with storm intensity, duration, or total rainfall. When the correction for wind effect on angle of raindrop inclination is included, the percent catch deficiency of the standard gage was reduced from 11 percent to 6 percent. The remaining errors may be attributed to wind effects (streamline vs. turbulent flow), nonrandom errors, or other unknown sources.     

THE DILUTION/FLUSHING TECHNIQUE IN LAKE RESTORATION1

ABSTRACT: Dilution/flushing has been documented as an effective restoration technique to restore eutrophic Moses and Green Lakes in Washington State. The dilution water added to both lakes was low in nitrogen and phosphorus content relative to the lake or normal input water. Consequently, lake nutrient content dropped predictably. Dilution or flushing rates were about ten times normal during the spring-summer periods in Moses Lake and three times normal on an annual basis in Green Lake. Improvement in quality (nutrients, algae, and transparency) was on the order of 50 percent in Moses Lake and even greater in Green Lake. The facilities for supplying dilution water were largely in place for the cited lakes; thus, costs for water transport were minimal. Available facilities, and therefore, costs, for water transport would usually vary greatly, however. Achieving maximum benefit from the technique may be more limited by availability of low nutrient water rather than facilities costs. Quality improvement may occur from physical effects of algal cell washout and water column instability if only high nutrient water is available.     

DISSOLVED OXYGEN IN INTRAGRAVEL WATER OF THREE TRIBUTARIES TO REDWOOD CREEK,HUMBOLDT COUNTY,CALIFORNIA1

ABSTRACT: As part of a study of Redwood National Park in north-western California, an investigation was conducted from June to November 1974 on intragravel dissolved oxygen and sediment in three tributaries to Redwood Creek, a major coastal stream that flows through Redwood National Park. Of concern was whether the intragravel environment of streams in logged and unlogged redwood-forested drainage basins was different. The tributary in the unlogged drainage basin had lower percentages of fine streambed sediment than either of the tributaries in logged drainage basins. Concentration and percentage saturation of dissolved oxygen of intragravel water were highest in the stream in the unlogged drainage basin, intermediate in the stream in the patch-cut drainage basin, and lowest in the stream in the clear-cut drainage basin. The differences in intragravel dissolved-oxygen conditions among the three tributaries are attributed chiefly to differences in their interchange of surface and intragravel water. The larger quantities of fine streambed sediment in the two streams in logged basins may have reduced the permeability of the streambeds and hence their capacity to interchange surface and intragravel water. However, differences in the lithology of the three tributary drainage basins examined may contribute to the differences in the percentage of fine sediments observed among the streams, even in the absence of logging.     

DESIGN OF AN INDEX OF WATER QUALITY1

ABSTRACT: This paper describes the formulation of an Index of Water Quality to evaluate the level of pollution in fresh water. A Four-Round Delphi equation, using a panel of seven nationally recognized water scientists, was performed to ascertain the pollutants to be included in the index, the relationship between the quantity of these pollutants in the water and the resulting quality of the water, and the importance of each pollution variable to each water use as well as to overall pollution. A multiplicative index was used to bring the pollutants together into one system.     

ACCOMMODATING CHANGE OF BACTERIAL INDICATORS IN LONG TERM WATER QUALITY DATASETS1

ABSTRACT: In 1996, the State of Oregon adopted a water quality standard based on Escherichia coli (E. coli), recognizing E. coli as an indicator of pathogenic potential. The Oregon Department of Environmental Quality (DEQ) began analysis for E. coli that same year. The Oregon DEQ continued collection and analysis of fecal coliform (a prior indicator organism) for data input to bacterial loading models and the Oregon Water Quality Index (OWQI). The OWQI is a primary indicator of general water quality for the Oregon DEQ and the Oregon Progress Board. The objective of this study was to develop a regression relationship between fecal coliform and E. coli. This relationship would fill data gaps and extend water quality models and indicators. Water quality policy is better informed by the ability of these extended water quality models to determine whether water quality meets present or would have met past bacterial standards. Monitoring resources spent on dual bacterial analyses could be conserved. This study also showed that changes to OWQI values (as a result of changing bacterial indicators) were minimal, and corresponded to improved characterization of water quality with respect to pathogenic potential.     

MULTIVARIATE TREND TESTING OF LAKE WATER QUALITY1

ABSTRACT: Multivariate methods of trend analysis offer the potential for higher power in detecting gradual water quality changes as compared to multiple applications of univariate tests. Simulation experiments were used to investigate the power advantages of multivariate methods for both linear model and Mann-Kendall based approaches. The experiments focused on quarterly observations of three water quality variables with no serial correlation and with several different intervariable correlation structures. The multivariate methods were generally more powerful than the univariate methods, offering the greatest advantage in situations where water quality variables were positively correlated with trends in opposing directions. For illustration, both the univariate and multivariate versions of the Mann-Kendall based tests were applied to case study data from several lakes in Maine and New York which have been sampled as part of EPA's long term monitoring study of acid precipitation effects.     

OPTIMAL ALLOCATION OF WATER QUALITY CONTROLS IN URBANIZING RIVER BASINS1

ABSTRACT: Urbanizing river basins in the west are encountering serious water quality degradation resulting from the expanded water utilization. In order to avoid aggravating such conditions, water quality controls need to be implemented. The important questions are, therefore, where and how to impose such constraints on the urban and agricultural sectors to achieve the desired level of pollution control. An application of the model developed to address such questions is made in the Utah Lake drainage area of Central Utah as a test of the model's utility. The region is subdivided into five major sub-basins containing both municipal and agricultural water demands. A submodel of each sub-basin is developed which optimizes the water quality control strategies by linking the urban to the agricultural uses and then evaluating the levels of control for each sector. From these results, a cost-effectiveness function for each sub-basin is generated. By jointly considering the cost-effectiveness relationship for each sub-basin, an optimum policy for the entire basin is determined.     

COALBED METHANE PRODUCT WATER CHEMISTRY IN THREE WYOMING WATERSHEDS1

ABSTRACT: The Powder River Basin in Wyoming has become one of the most active areas of coalbed methane (CBM) development in the western United States. Extraction of methane from coalbeds requires pumping of aquifer water, which is called product water. Two to ten extraction wells are manifolded into one discharge point and product water is released into nearby unlined holding ponds. The objective of this study was to evaluate the chemistry, salinity, and sodicity of CBM product water at discharge points and associated holding ponds as a function of watershed. The product water samples from the discharge points and associated holding ponds were collected from the Cheyenne River (CHR), Belle Fourche River (BFR), and Little Powder River (LPR) watersheds during the summers of 1999 and 2000. These samples were analyzed for pH, electrical conductivity (EC), total dissolved solids (TDS), alkalinity, sodium (Na), calcium (Ca), magnesium (Mg), potassium (K), sulfate (SO₄^2‐), and chloride (C^1‐). From the chemical data, practical sodium adsorption ratio (SARp) and true sodium adsorption ratio (SARt) were calculated for the CBM discharge water and pond water. The pH, EC, TDS, alkalinity, Na, Ca, Mg, K, SARp, and SARt of CBM discharge water increased significantly moving north from the CHR watershed to the LPR watershed. CBM discharge water in associated holding ponds showed significant increases in EC, TDS, alkalinity, Na, K, SARp, and SARt moving north from the CHR to the LPR watershed. Within watersheds, the only significant change was an increase in pH from 7.21 to 8.26 between discharge points and holding ponds in the LPR watershed. However, the LPR and BFR exhibited larger changes in mean chemistry values in pH, salinity (EC, TDS), and sodicity (SAR) between CBM product water discharges and associated holding ponds than the CHR watershed. For instance, the mean EC and TDS of CBM product water in LPR increased from 1.93 to 2.09 dS/m, and froml,232 to 1,336 mg/L, respectively, between discharge and pond waters. The CHR exhibited no change in EC, TDS, Na, or SAR between discharge water and pond water. Also, while not statistically significant, mean alkalinity of CBM product water in BFR and LPR watersheds decreased from 9.81 to 8.01 meq/L and from 19.87 to 18.14 meq/L, respectively, between discharge and pond waters. The results of this study suggest that release of CBM product water onto the rangelands of BFR and LPR watersheds may precipitate calcium carbonate (CaCO₃) in soils, which in turn may decrease infiltration and increase runoff and erosion. Thus, use of CBM product water for irrigation in LPR and BFR watersheds may require careful planning based on water pH, EC, alkalinity, Na, and SAR, as well as local soil physical and chemical properties.