Water quality and restoration in a coastal subdivision stormwater pond

Stormwater ponds are commonly used in residential and commercial areas to control flooding. The accumulation of urban contaminants in stormwater ponds can lead to a number of water quality problems including high nutrient, chemical contaminant, and bacterial levels. This study examined the interaction between land use and coastal pond water quality in a South Carolina residential subdivision pond. Eutrophic levels of chlorophyll and phosphorus were present in all seasons. Harmful cyanobacterial blooms were prevalent during the summer months. Microcystin toxin and fecal coliform bacteria levels were measured that exceeded health and safety standards. Low concentrations of herbicides (atrazine and 2,4-D) were also detected during summer months. Drainage from the stormwater pond may transport contaminants into the adjacent tidal creek and estuary. A survey of residents within the pond's watershed indicated poor pet waste management and frequent use of fertilizers and pesticides as possible contamination sources. Educational and outreach activities were provided to community members to create an awareness of the water quality conditions in the pond. Pond management strategies were then recommended, and selected mitigation actions were implemented. Water quality problems identified in this study have been observed in other coastal stormwater ponds of varying size and salinity, leading this project to serve as a potential model for coastal stormwater pond management.     

Full Water‐Cycle Monitoring in an Urban Catchment Reveals Unexpected Water Transfers (Detroit MI,USA)

A goal in urban water management is to reduce the volume of stormwater runoff in urban systems and the effect of combined sewer overflows into receiving waters. Effective management of stormwater runoff in urban systems requires an accounting of various components of the urban water balance. To that end, precipitation, evapotranspiration (ET), sewer flow, and groundwater in a 3.40‐hectare sewershed in Detroit, Michigan were monitored to capture the response of the sewershed to stormwater flow prior to implementation of stormwater control measures. Monitoring results indicate that stormflow in sewers was not initiated unless rain depth was 3.6 mm or greater. ET removed more than 40% of the precipitation in the sewershed, whereas pipe flow accounted for 19%–85% of the losses. Flows within the sewer that could not be associated with direct precipitation indicate an unexpected exchange of water between the leaky sewer and the groundwater system, pathways through abandoned or failing residential infrastructure, or a combination of both. Groundwater data indicate that groundwater flows into the leaky combined sewer rather than out. This research demonstrates that urban hydrologic fluxes can modulate the local water cycle in complex ways which affect the efficiency of the wastewater system, effectiveness of stormwater management, and, ultimately, public health.     

Sustainable use of stormwater for irrigation case study: Manly Golf Course

Sustainability has become an increasingly used term, but what does it mean in terms of practice. This research will look at the harvesting of captured stormwater for the irrigation of urban playing fields and what the implications are for catchment hydrology, local community, and local council. This research aims to identify, understand and determine the catchment conditions that may hinder the stormwater quality and quantity for capture and reuse, as well as determining whether the stormwater harvesting will be sustainable. Research methods for this project will include systemic analysis in order to further investigate the assumptions being made in the study. Manly Golf Club has relied on groundwater extraction supplemented by potable supplies for irrigation, however potable supplies are no longer available. It has been proposed to provide irrigation supplies from stormwater via onsite storage and groundwater recharge. Monitored stormwater entering the Golf Course from the adjacent Cemetery Creek sub-catchment for pollutants, have indicated that it may be suitable for irrigation with treatment and may reduce problems generated by overuse of groundwater. The proposal will provide environmental benefit through reduced pollution loads being discharged directly to receiving waters and cessation of use of potable supplies by the Club. Social and economic benefits are expected to be gained and will be monitored as part of an ongoing research program.     

Accretion of Nutrients and Sediment by a Constructed Stormwater Treatment Wetland in the Lake Tahoe Basin

This unique study evaluates the cumulative 16‐year lifetime performance of a wetland retention basin designed to treat stormwater runoff. Sediment cores were extracted prior to basin excavation and restoration to evaluate accretion rates and the origin of materials, retention characteristics of fine particulate matter, and overall pollutant removal efficiency. The sediment and organic layers together accreted 3.2 cm of depth per year, and 7.0 kg/m²/yr of inorganic material. Average annual accretion rates in g/m²/yr were as follows: C, 280; N, 17.7; P, 3.74; S, 3.80; Fe, 194; Mn, 2.68; Ca, 30.8; Mg, 30.7; K, 12.2; Na, 2.54; Zn, 0.858; Cu, 0.203; and B, 0.03. The accretion of C, N, P and sediment was comparable to nonwastewater treatment wetlands, overall, and relatively efficient for stormwater treatment wetlands. Comparison of particle size distribution between sediment cores and suspended solids in stormwater runoff indicated the wetland was effective at removing fine particles, with sediment cores containing 25% clay and 56% silt. A majority of the accretion of most metals and P could be attributed to efficient trapping of allochthonous material, while over half the accretion of C and N could be attributed to accumulation of autochthonous organic matter. Stormwater treatment was shown to be effective when physical properties of a retention basin are combined with the biological processes of a wetland, although sediment accretion can be relatively rapid.     

CONCENTRATION AND SOURCES OF FECAL AND ORGANIC POLLUTION IN AN AGRICULTURAL WATERSHED1

ABSTRACT: Fecal contamination and organic pollution of an agricultural drainage in northeast Indiana was high. Bacterial counts (total coliform, TC; fecal coliform, FC; and fecal streptococcus, FS) and biochemical oxygen demand (BOD) were used to assess waste concentrations. Coliform counts indicated that sections of the drainage receiving septic effluent had waste concentrations far in excess of public health standards (mean FC = 550,000/100 ml). Areas of drainage remote from septic tank pollution were found to occasionally meet federal public health standards for whole body contact recreation but generally these areas had twice the allowable limit of 200 FC/100 ml. Bacterial contamination was highest during runoff events when the median values for TC, FC, and FS were 5, 3, and 17 times greater, respectively, than the median values during low stream discharge. Surface flows carried contaminants from unconfined livestock operations and fecally contaminated sediment was transported by high waters. During one runoff event a BOD loading of 36.7 kg/km² was recorded and the peak BOD concentration observed was 16 mg/l. A discharge of liquid manure from a confined livestock operation caused a major fish kill. Pollution from septic tanks and unconfined livestock is greatest at high stream discharge when dilution reduces the impact on aquatic life.     

Coupling PCSWMM and WASP to Evaluate Green Stormwater Infrastructure Impacts to Storm Sediment Loads in an Urban Watershed

We coupled rainfall–runoff and instream water quality models to evaluate total suspended solids (TSS) in Wissahickon Creek, a mid‐sized urban stream near Philadelphia, Pennsylvania. Using stormwater runoff and instream field data, we calibrated the model at a subdaily scale and focused on storm responses. We demonstrate that treating event mean concentrations as a calibration parameter rather than a fixed input can substantially improve model performance. Urban stormwater TSS concentrations vary widely in time and space and are difficult to represent simply. Suspended and deposited sediment pose independent stressors to stream biota and model results suggest that both currently impair stream health in Wissahickon Creek. Retrofitting existing detention basins to prioritize infiltration reduced instream TSS loads by 20%, suggesting that infiltration mitigates sediment more effectively than detention. Infiltrating stormwater from 30% of the watershed reduced instream TSS loads by 47% and cut the frequency of TSS exceeding 100 mg/L by half. Settled loads and the frequency of high TSS values were reduced by a smaller fraction than suspended loads and duration at high TSS values. A widely distributed network of infiltration‐focused projects is an effective stormwater management strategy to mitigate sediment stress. Coupling rainfall–runoff and water quality models is an important way to integrate watershed‐wide impacts and evaluate how management directly affects urban stream health.     

Sediment Quality Assessment in the Gulf of Gdańsk (Baltic Sea) Using Complementary Lines of Evidence

Sediments from Polish coastal environments were classified by a quality assessment approach that took into account trace metal and organic micropollutant concentrations, grain-size distribution, and organic carbon content. Generally, no benthic organisms were found at sites where sediments were classified as heavily polluted. However, areas characterized by a moderate contamination showed a variable composition of the benthic community and changing bioaccumulation patterns; therefore, no single species found in the Gulf of Gdańsk could be considered representative of the whole benthic environment. Although sediment monitoring must be considered a suitable tool to detect hot-spot pollution areas in coastal and inland waters, it should be complemented by bioaccumulation measurements to evaluate the actual risk posed by contaminants to benthic organisms. This “biological information” allows a better appreciation of the real benthic infaunal community exposure to chemicals and can usefully complement the existing sediment quality guidelines.     

Water Supply and Stormwater Management Benefits of Residential Rainwater Harvesting in U.S. Cities

This article presents an analysis of the projected performance of urban residential rainwater harvesting systems in the United States (U.S.). The objectives are to quantify for 23 cities in seven climatic regions (1) water supply provided from rainwater harvested at a residential parcel and (2) stormwater runoff reduction from a residential drainage catchment. Water‐saving efficiency is determined using a water‐balance approach applied at a daily time step for a range of rainwater cistern sizes. The results show that performance is a function of cistern size and climatic pattern. A single rain barrel (190 l [50 gal]) installed at a residential parcel is able to provide approximately 50% water‐saving efficiency for the nonpotable indoor water demand scenario in cities of the East Coast, Southeast, Midwest, and Pacific Northwest, but <30% water‐saving efficiency in cities of the Mountain West, Southwest, and most of California. Stormwater management benefits are quantified using the U.S. Environmental Protection Agency Storm Water Management Model. The results indicate that rainwater harvesting can reduce stormwater runoff volume up to 20% in semiarid regions, and less in regions receiving greater rainfall amounts for a long‐term simulation. Overall, the results suggest that U.S. cities and individual residents can benefit from implementing rainwater harvesting as a stormwater control measure and as an alternative source of water.     

Permeability predictions for sand-clogged Portland cement pervious concrete pavement systems

Pervious concrete is an alternative paving surface that can be used to reduce the nonpoint source pollution effects of stormwater runoff from paved surfaces such as roadways and parking lots by allowing some of the rainfall to permeate into the ground below. This infiltration rate may be adversely affected by clogging of the system, particularly clogging or covering by sand in coastal areas. A theoretical relation was developed between the effective permeability of a sand-clogged pervious concrete block, the permeability of sand, and the porosity of the unclogged block. Permeabilities were then measured for Portland cement pervious concrete systems fully covered with extra fine sand in a flume using simulated rainfalls. The experimental results correlated well with the theoretical calculated permeability of the pervious concrete system for pervious concrete systems fully covered on the surface with sand. Two different slopes (2% and 10%) were used. Rainfall rates were simulated for the combination of direct rainfall (passive runoff) and for additional stormwater runoff from adjacent areas (active runoff). A typical pervious concrete block will allow water to pass through at flow rates greater than 0.2 cm/s and a typical extra fine sand will have a permeability of approximately 0.02 cm/s. The limit of the system with complete sand coverage resulted in an effective system permeability of approximately 0.004 cm/s which is similar to the rainfall intensity of a 30 min duration, 100-year frequency event in the southeastern United States. The results obtained are important in designing and evaluating pervious concrete as a paving surface within watershed management systems for controlling the quantity of runoff.     

Bioremediation of Acidic and Metalliferous Drainage (AMD) through organic carbon amendment by municipal sewage and green waste

Pit lakes (abandoned flooded mine pits) represent a potentially valuable water resource in hot arid regions. However, pit lake water is often characterised by low pH with high dissolved metal concentrations resulting from Acidic and Metalliferous Drainage (AMD). Addition of organic matter to pit lakes to enhance microbial sulphate reduction is a potential cost effective remediation strategy. However, cost and availability of suitable organic substrates are often limiting. Nevertheless, large quantities of sewage and green waste (organic garden waste) are often available at mine sites from nearby service towns. We treated AMD pit lake water (pH 2.4) from tropical, North Queensland, Australia, with primary-treated sewage sludge, green waste, and a mixture of sewage and green waste (1:1) in a controlled microcosm experiment (4.5 L). Treatments were assessed at two different rates of organic loading of 16:1 and 32:1 pit water:organic matter by mass. Combined green waste and sewage treatment was the optimal treatment with water pH increased to 5.5 in only 145 days with decreases of dissolved metal concentrations. Results indicated that green waste was a key component in the pH increase and concomitant heavy metal removal. Water quality remediation was primarily due to microbially-mediated sulphate reduction. The net result of this process was removal of sulphate and metal solutes to sediment mainly as monosulfides. During the treatment process NH(3) and H(2)S gases were produced, albeit at below concentrations of concern. Total coliforms were abundant in all green waste-treatments, however, faecal coliforms were absent from all treatments. This study demonstrates addition of low-grade organic materials has promise for bioremediation of acidic waters and warrants further experimental investigation into feasibility at higher scales of application such as pit lakes.     

Impediments and Solutions to Sustainable,Watershed-Scale Urban Stormwater Management: Lessons from Australia and the United States

In urban and suburban areas, stormwater runoff is a primary stressor on surface waters. Conventional urban stormwater drainage systems often route runoff directly to streams and rivers, thus exacerbating pollutant inputs and hydrologic disturbance, and resulting in the degradation of ecosystem structure and function. Decentralized stormwater management tools, such as low impact development (LID) or water sensitive urban design (WSUD), may offer a more sustainable solution to stormwater management if implemented at a watershed scale. These tools are designed to pond, infiltrate, and harvest water at the source, encouraging evaporation, evapotranspiration, groundwater recharge, and re-use of stormwater. While there are numerous demonstrations of WSUD practices, there are few examples of widespread implementation at a watershed scale with the explicit objective of protecting or restoring a receiving stream. This article identifies seven major impediments to sustainable urban stormwater management: (1) uncertainties in performance and cost, (2) insufficient engineering standards and guidelines, (3) fragmented responsibilities, (4) lack of institutional capacity, (5) lack of legislative mandate, (6) lack of funding and effective market incentives, and (7) resistance to change. By comparing experiences from Australia and the United States, two developed countries with existing conventional stormwater infrastructure and escalating stream ecosystem degradation, we highlight challenges facing sustainable urban stormwater management and offer several examples of successful, regional WSUD implementation. We conclude by identifying solutions to each of the seven impediments that, when employed separately or in combination, should encourage widespread implementation of WSUD with watershed-based goals to protect human health and safety, and stream ecosystems.     

THE EFFECT OF RESIDENTIAL DEVELOPMENT ON GROUND‐WATER QUALITY NEAR DETROIT,MICHIGAN1

ABSTRACT: Two water‐quality studies were done on the outskirts of the Detroit metropolitan area to determine how recent residential development has affected ground‐water quality. Pairs of monitor and domestic wells were sampled in areas where residential land use overlies glacial outwash deposits. Young, shallow waters had significantly higher median concentrations of nitrate, chloride, and dissolved solids than older, deeper waters. Analysis of chloride/bromide ratios indicates that elevated salinities are due to human activities rather than natural factors, such as upward migration of brine. Trace concentrations of volatile organic compounds were detected in samples from 97 percent of the monitor wells. Pesticides were detected infrequently even though they are routinely applied to lawns and roadways in the study area. The greatest influence on ground‐water quality appears to be from septic‐system effluent (domestic sewage, household solvents, water‐softener backwash) and infiltration of storm‐water runoff from paved surfaces (road salt, fuel residue). No health‐related drinking‐water standards were exceeded in samples from domestic wells. However, the effects of human activities are apparent in 76 percent of young waters, and at depths far below 25 feet, which is the current minimum well‐depth requirement.     

Phosphorus runoff from incorporated and surface-applied liquid swine manure and phosphorus fertilizer

Excessive fertilization with organic and/or inorganic P amendments to cropland increases the potential risk of P loss to surface waters. The objective of this study was to evaluate the effects of soil test P level, source, and application method of P amendments on P in runoff following soybean [Glycine max (L.) Merr.]. The treatments consisted of two rates of swine (Sus scrofa domestica) liquid manure surface-applied and injected, 54 kg P ha(-1) triple superphosphate (TSP) surface-applied and incorporated, and a control with and without chisel-plowing. Rainfall simulations were conducted one month (1MO) and six months (6MO) after P amendment application for 2 yr. Soil injection of swine manure compared with surface application resulted in runoff P concentration decreases of 93, 82, and 94%, and P load decreases of 99, 94, and 99% for dissolved reactive phosphorus (DRP), total phosphorus (TP), and algal-available phosphorus (AAP), respectively. Incorporation of TSP also reduced P concentration in runoff significantly. Runoff P concentration and load from incorporated amendments did not differ from the control. Factors most strongly related to P in runoff from the incorporated treatments included Bray P1 soil extraction value for DRP concentration, and Bray P1 and sediment content in runoff for AAP and TP concentration and load. Injecting manure and chisel-plowing inorganic fertilizer reduced runoff P losses, decreased runoff volumes, and increased the time to runoff, thus minimizing the potential risk of surface water contamination. After incorporating the P amendments, controlling erosion is the main target to minimize TP losses from agricultural soils.     

Impact of Residential Soil Disturbance on Infiltration Rate and Stormwater Runoff1

Woltemade, Christopher J., 2010. Impact of Residential Soil Disturbance on Infiltration Rate and Stormwater Runoff. Journal of the American Water Resources Association (JAWRA) 46(4): 700-711. DOI: 10.1111/j.1752-1688.2010.00442.x Abstract: Soil disturbances such as excavation and compaction in residential developments affect lawn infiltration rates and stormwater runoff. These effects were investigated via measuring saturated infiltration rates at 108 residential sites and 18 agricultural sites near Shippensburg, south-central Pennsylvania, using a double-ring infiltrometer. Residential sites included four neighborhoods distributed across three soil series classified as hydrologic soil group (HSG) B. Additional parcel data included date of house construction, percentage impervious area, lawn condition, and woody vegetation condition. Measured infiltration rates ranged from 0 to >40 cm/hour. Analysis of variance indicated significantly different mean infiltration rates (p < 0.001) for lots constructed pre-2000 (9.0 cm/hour) and those constructed post-2000 (2.8 cm/hour). Test results were used to determine a “field-tested” HSG for each site, representing disturbed soil conditions. Stormwater runoff was estimated from residential lots for a range of 24-hour design storms using the TR-55 model and several alternative methods of determining curve numbers, including five different representations of soil conditions. Curve numbers and stormwater runoff were substantially higher when based on field-tested HSGs for lots constructed post-2000 compared with lots built pre-2000 and when based on the HSG for undisturbed soils, documenting the magnitude of possible error in stormwater runoff models that neglect soil disturbance.     

Use of reactive materials to bind phosphorus

Phosphorus (P) losses from agricultural soils have caused surface water quality impairment in many regions of the world, including The Netherlands. Due to the large amounts of P accumulated in Dutch soils, the generic fertilizer and manure policy will not be sufficient to reach in time the surface water quality standards of the European Water Framework Directive. Additional measures must be considered to further reduce P enrichment of surface waters. One option is to immobilize P in soils or manure or to trap P when it moves through the landscape by using reactive materials with a large capacity to retain P. We characterized and tested two byproducts of the process of purification of deep groundwater for drinking water that could be used as reactive materials: iron sludge and iron-coated sand. Both materials contain low amounts of inorganic contaminants, which also have a low (bio)availability, and bound a large amount of P. We could describe sorption of P to the iron sludge in batch experiments well with the kinetic Freundlich equation (Q = × t (m) × C(n)). Kinetics had a large influence on P sorption in batch and column experiments and should be taken into account when iron-containing materials are tested for their capability to immobilize or trap P. A negative aspect of the iron sludge is its low hydraulic conductivity; even when mixed with pure sand to a mixture containing 20% sludge, the conductivity was very low, and only 10% sludge may be needed before application is possible in filters or barriers for removing P from groundwater. Due to its much higher hydraulic conductivity, iron-coated sand has greater potential for use under field conditions. Immobilizing P could be an option for using iron sludge as a reactive material.     

土壤中污染物迁移模型在油田环境影响评价中的应用

在石油的生产、运输、贮存以及炼制等过程中都存在泄油、漏油风险,各生产过程中的废弃物,如油类、重金属等各种化学物质也会危害水土环境,进而危及当地地下水源。文章分析了油田企业污染物对土壤及地下水的主要污染途径,提出了将污染物在土壤中的迁移模型用于预测污染物浓度的方法。建立了污染物由土壤迁至室内空气、地下水、农作物及由地下水转移到地表水的迁移数学模型,该模型可以运用于油田环境影响评价。     

WATER QUALITY OF STORMWATER RUNOFF FROM TEN INDUSTRIAL SITES1

ABSTRACT: This study was to designed to determine concentrations of selected metals, organic compounds, pesticides, and conventional pollutants in stormwater runoff from two North Carolina businesses in each of the following five general industrial groups: auto salvage, metal fabrication, scrap and recycling, vehicle maintenance, and wood preserving facilities. The sampling procedure involved collecting a first flush sample of runoff from a single storm event and both first flush and composite samples of runoff from three consecutive storm events. Analysis of samples collected during the first flush indicated that zinc and copper were the most common of the 13 metals included in the analysis. Additional analysis documented that several volatile organic, semi-volatile organic, or pesticide compounds including acrolein, methylene chloride, xylenes, toluene, tetrachloroethylene, trichloroethylene, pentachlorophenol, and aldrin were also found in the first flush samples. Concentrations of aggregate organics, nitrogen, phosphorus, and sediment were determined in both first flush and three-hour composite samples. Concentrations of pollutants in first flush samples were similar to those in corresponding composite samples.     

WATER QUALITY TRENDS IN LAKE TOHOPEKALIGA,FLORIDA, USA: RESPONSES TO WATERSHED MANAGEMENT1

ABSTRACT: Water quality in eutrophic Lake Tohopekaliga, Florida, improved markedly from 1982 to 1992 as a result of reductions in phosphorus and nitrogen loading to the lake. Annual budgets of water, chloride, phosphorus and nitrogen were constructed for the lake, and indicate it is a sink for phosphorus and a source for nitrogen. Water column concentrations of total phosphorus, soluble reactive phosphorus, total nitrogen, dissolved inorganic nitrogen, and chlorophyll a all declined as external inputs of nutrients decreased. Water column nitrogen: phosphorus ratios have increased, suggesting a probable shift from nitrogen- to phosphorus-limitation. This apparent shift in nutrient limitation status also is supported by comparisons of the mean Trophic State Indices for phosphorus, nitrogen, and chlorophyll a. These improvements in water quality are attributed to the diversion of wastewater treatment plant effluent from the lake, and the increased use of wet retention ponds for stormwater runoff.     

Watershed scale assessment of nitrogen and phosphorus loadings in the Indian River Lagoon basin,Florida

There is a growing evidence that the ecological and biological integrity of the lagoon has declined during the last 50 years, probably due to the decline in water quality. Establishment of a watershed scale seagrass-based nutrient load assessment is the major aim of water quality management in the Indian River Lagoon (IRL). Best estimate loadings incorporate wet and dry deposition, surface water, groundwater, sediment nutrient flux, and point source effluent discharge data. On the average, the IRL is receiving annual external loadings of 832, 645 and 94,476kg of total nitrogen (TN) and total phosphorus (TP), respectively, from stormwater discharges and agricultural runoff. The average internal cycling of TN and TP from sediment deposits in the IRL was about 42,640kg TN and 1050kg TPyr(-1). Indirect evidence suggests that atmospheric deposition has played a role in the ongoing nutrient enrichment in the IRL. The estimated total atmospheric deposition of TN and TP was about 32,940 and 824kgyr(-1), while groundwater contribution was about 84,920 and 24,275kgyr(-1), respectively, to the surface waters of the IRL. The estimated annual contribution of point effluent discharge was about 60,408kg TN and 7248kg TP. In total, the IRL basin is receiving an annual loading of about 1,053,553kg TN and 127,873kg TP. With these results, it is clear that the current rate of nutrient loadings is causing a shift in the primary producers of the IRL from macrophyte to phytoplankton- or algal-based system. The goal is to reverse that shift, to attain and maintain a macrophyte-based estuarine system in the IRL.     

REAUTHORIZING THE CLEAN WATER ACT: LOOKING TO TANGIBLE VALUES1

ABSTRACT: The degree of progress achieved under the 1972 Clean Water Act is reviewed by reference to traditional measures of program implementation, and to evidence of tangible, or “real-world” progress, such as beach closures, drinking water contamination, fishing bans and advisories, species health, and habitat degradation. Significant progress has been made in reducing pollution from point sources, but large point source releases of toxic and other pollutants remain. Little progress has been made in addressing runoff pollution, and in protecting aquatic habitats. Clean Water Act reauthorization should focus on pollution prevention to reduce further the release of toxics by point sources, a new program of mandatory but flexible controls on sources of runoff, and watershed protection programs to promote habitat protection and restoration. Economic factors should be considered in Clean Water Act programs, but must be balanced against scientific and governmental factors as well.