Meet Water Quality Objectives Research Articles

Monitoring to detect changes in water quality to meet policy objectives

Detecting change in water quality is key to providing evidence of progress towards meeting water quality objectives. A key measure for detecting change is statistical power. Here we calculate statistical power for all regularly (monthly) monitored streams in New Zealand to test the effectiveness of monitoring for policy that aims to decrease contaminant (phosphorus and nitrogen species, E. coli and visual clarity) concentrations to threshold levels in 5 or 20 years. While > 95% of all monitored sites had sufficient power and samples to detect change in nutrients and clarity over 20 years, on average, sampling frequency would have to double to detect changes in E. coli. Furthermore, to detect changes in 5 years, sampling for clarity, dissolved reactive phosphorus and E. coli would have to increase up to fivefold. The cost of sampling was predicted to increase 5.3 and 4.1 times for 5 and 20 years, respectively. A national model of statistical power was used to demonstrate that a similar number of samples (and cost) would be required for any new monitoring sites. Our work suggests that demonstrating the outcomes of implementing policy for water quality improvement may not occur without a step change in investment into monitoring systems. Emerging sampling technologies have potential to reduce the cost, but existing monitoring networks may also have to be rationalised to provide evidence that water quality is meeting objectives. Our study has important implications for investment decisions involving balancing the need for intensively sampled sites where changes in water quality occur rapidly versus other sites which provide long-term time series.

A versatile nanocomposite Fe0@SiO2@CaO2 for reductive, oxidative, and coagulation removal of organic and inorganic contaminants from water

Water scarcity is one of the most pressing global challenges and limits economic and social development. Multiple processes of current technologies for water purification are needed to meet water quality objectives due to their contaminant-specific removal capability. Here, we developed Fe0@SiO2@CaO2 nanocomposite with three layers of core–shell structure that could achieve an array of water contaminants removal by oxidation, reduction, and flocculation. >99 % of 50 mg/L tetracycline, 20 mg/L pentachlorophenol, 450 mg/L Cd(Ⅱ), 20 mg/L Cr(Ⅵ), or 80 mg/L P (in form of PO43−) was removed by 2 g/L Fe0@SiO2@CaO2 in 24 h. Moreover, Fe0@SiO2@CaO2 (2 g/L) showed an excellent performance in turbidity removal (239 mg/L kaolinite suspension, removal rate > 99 %) and water decolorization (50 mg/L humic acid, removal rate > 93 %). Cd(II) and Cr(VI) could be reduced to Cd(0) and Cr(III), respectively, through electronic reduction reactions using Fe0 and •H, which is formed during the reaction Fe0 + 2H+→2•H + Fe2+; Cd(Ⅱ) and the formed Cr(III) could coprecipitate with the formed orthosilicic acid and OH−. The removal of P was mainly resulted from the coordination with released Ca2+ and iron compounds. Charge neutralization by nanocomposite and coagulation with the products from nanocomposite transformation were responsible for the kaolinite removal. Reduction by •H and Fe0, oxidation by •OH derived from the Fenton reaction, and/or coagulation accounted for the organic contaminant removal. This work provides a novel material that can be used to simultaneously remove a range of contaminants in wastewater treatment.

Turbidity informed real-time control of a dry extended detention basin: a case study

This research investigated the impact and use of real-time water quality data in a dry extended detention basin retrofitted with a controllable valve and a turbidity sensor with the goal of more consistently meeting water quality objectives.

Improved Microbial Water Quality Associated with Best Management Practices on Coastal Dairies and Livestock Grazing Operations

Dairy and livestock grazing operations can introduce pollutants such as fecal coliform to surface waters, posing risk to human health and ecological conditions. Agricultural best management practices (BMPs) that increase control of manure, runoff, and animal access to waterways can reduce deposition of microbial pollution into streams. Between 2000 and 2013, we monitored water quality (fecal indicator bacteria [FIB] consisting of fecal coliform [FC] and Escherichia coli [EC]) in three coastal watersheds that encompass intensively managed dairies, beef cattle grazing operations, and public use at Point Reyes National Seashore in Marin County, California. Concurrently, approximately 30 BMPs were implemented to manage cattle and improve dairy infrastructure. We also monitored a fourth adjacent watershed without any BMPs and limited direct livestock influence. The primary FIB parameter was changed from FC to EC midway through the study in 2007, so we combined FC data from 2000 to 2006 with EC data from 2007 to 2013 using previously published EC/FC ratios and data from this study to create a continuous time series. Competing Bayesian generalized linear mixed models examined whether FIB was best explained by year, 24-h rainfall, season, or annual rainfall and compared results with numeric regulatory objectives for surface waters. FIB from 2000 to 2013 declined at all 13 water quality stations that were downstream of BMPs implemented during the study, while there was a slight positive trend in the adjacent watershed without BMPs and limited livestock influence. There was a 54−99% reduction in FIB with a sixfold increase in the frequency of samples meeting regulatory criteria over the study period, and results were robust to varying assumptions of the relationship between FC and EC. These findings indicate that targeted BMPs can effectively reduce FIB, increasing the probability of meeting water quality objectives across varying types of livestock operations.

Estimation of Rate Constants for Nutrient Transformations

Non-point source pollution of surface water is a major impediment to meet water quality objectives. Managing such pollution sources in a sustainable way is a key success factor in maintaining high water quality and to prevent eutrophication. Mathematical models are widely used to simulate ecological and water quality interactions in surface waters. Simulation errors may arise due to uncertainties of the structure, input data and the model parameters. In this study, an attempt has been made to estimate the rate constants for nutrient transformations in Kabini River located in Southern part of Karnataka state in India. The experimental results demonstrated both ammonia and nitrite oxidation. In the river water, DO concentration was 5.2 mg/L. After addition of pollutants it reduced to 3.9 mg/L. EC changed from 370 to 550 μS/cm. pH remained almost the same. At 320C, the rate constants for phosphate, nitrate, nitrite, potassium and ammonia were found to be 0.165, 0.21, 0.077, 0.0777 and 0.078/hr respectively. The results obtained clearly specify that the rate constants are concentration and temperature dependent.

Incorporating uncertainty and risk into decision making to reduce nitrogen inputs to impaired waters

This article aims to understand decision making under uncertainty and risk, with a case study on Cape Cod, Massachusetts. Decision makers need to consider imperfect information on the cost and effectiveness of advanced nitrogen-removing on-site wastewater treatment systems as options to mitigate water quality degradation. Research included modeling nitrogen load reduction to impaired coastal waters from seven treatment system technologies and eliciting expert knowledge on their costs. Predictions of nitrogen load removal and cost for each technology incorporated variation in effectiveness and uncertainty in household water use, costs, and expert confidence in costs. The predictions were evaluated using the Pareto efficiency concept to reveal tradeoffs between cost and effectiveness. The stochastic dominance index was used to identify preferred technologies for risk-averse decision making, assuming no further learning is possible. Lastly, the predictions were combined into a cost-effectiveness metric to estimate the expected payoff of implementing the best treatment system in the face of uncertainty and the expected payoff of learning which treatment systems are most cost-effective over time. The expected value of perfect information was calculated as the difference between the expected payoffs. Three technologies revealed Pareto efficient tradeoffs between cost and effectiveness, whereas one technology was the preferred risk-averse option in the absence of future learning. There was a high expected value of perfect information, which could motivate adaptive management on Cape Cod. This research demonstrated decision analysis methods to guide future research and decision making toward meeting water quality objectives and reducing uncertainty.

Actinia-like multifunctional nanocoagulant for single-step removal of water contaminants.

Current technologies for water purification are limited by their contaminant-specific removal capability, requiring multiple processes to meet water quality objectives. Here we show an innovative biomimetic micellar nanocoagulant that imitates the structure of Actinia, a marine predator that uses its tentacles to ensnare food, for the removal of an array of water contaminants with a single treatment step. The Actinia-like micellar nanocoagulant has a core-shell structure and readily disperses in water while maintaining a high stability against aggregation. To achieve effective coagulation, the nanocoagulant everts its configuration, similar to Actinia. The shell hydrolyses into 'flocs' and destabilizes and enmeshes colloidal particles while the core is exposed to water, like the extended tentacles of Actinia, and adsorbs the dissolved contaminants. The technology, with its ability to remove a broad spectrum of contaminants and produce high-quality water, has the potential to be a cost-effective replacement for current water treatment processes.

Assessing climate change impacts on the reliability of rainwater harvesting systems

Rainwater harvesting (RWH) systems recycle runoff, increasing the sustainability of water supplies; they may also reduce runoff discharges, and thus help meet water quality objectives. RWH systems receive runoff and thus will likely be impacted by changes in rainfall induced by climate change (CC). In this paper, we assess CC impacts on RWH with respect to the reliability of water supply, defined as the proportion of demands that are met; and the reliability of runoff capture, defined as the amount stored and reused, but not spilled. Hypothetical RWH systems with varying storage, rooftop catchments, irrigated areas, and indoor water demand for 17 locations across the U.S. were simulated for historical (1971–1998) and future (2041–2068) periods using downscaled climate model data assuming future medium-high greenhouse gas emissions. The largest change in runoff capture reliability would occur in Chicago (−12.4%) and Los Angeles (+12.3%), respectively. The largest change in water supply reliability would occur in Miami (+22%) and Los Angeles (−17.9%), respectively. The effectiveness of RWH systems for runoff capture is likely to be reduced in the eastern, northwestern, and southeastern U.S. Conversely, for most locations in the western, southern, and central U.S., RWH systems are expected to become less effective for water supply purposes. The additional storage needed to compensate for these reductions in water supply and/or runoff capture benefits was estimated. The results of this study can be used to design more resilient RWH systems with respect to CC, and thus maximize the dual objectives of RWH.

The use of a passive treatment system for the mitigation of acid mine drainage at the Williams Brothers Mine (California): pilot-scale study

A pilot-scale study was undertaken to assess the feasibility of using a passive treatment system to mitigate the acid mine drainage at the abandoned Williams Brothers Mine site, a remote site located in Sierra National Forest (California). The advantages of implementing passive treatment systems in remote or abandoned mine sites are their low energy and maintenance requirements compared to conventional systems. A pilot-scale system was designed and implemented at the site, which consisted of: (1) an aeration rock channel to facilitate oxidation of ferrous iron to ferric iron; (2) a sedimentation tank to collect iron oxyhydroxide precipitates that could lead to the clogging of the system; (3) a peat biofilter for the removal of dissolved iron and copper; (4) a sulphate-reducing bacteria reactor for the generation of alkalinity and consequent pH increase, and the removal of dissolved nickel, zinc, and residual dissolved iron and copper; and, (5) a re-aeration limestone channel to add alkalinity prior to effluent discharge into the natural receiving environment. The pilot-scale system was monitored over a 17-month period (500 days from July 2007 to November 2008) and performance was determined by monitoring the pH, sulphate and dissolved metal concentrations of the influent acid mine drainage and the effluents from the peat biofilter and sulphate reducing bacteria reactor. A decrease in sulphate concentration was noted in the sulphate reducing bacteria reactor, suggesting sulphate reducing bacteria activity and alkalinity generation. The effluent pH from the system increased from as low as 4.5 to above 6.0, but remained below water quality objectives for the San Joaquin River Basin. Dissolved copper, nickel and zinc removal to below water quality objectives was noted in the peat biofilter to below water quality objectives. Dissolved iron and manganese removal was also observed in the sulphate reducing bacteria reactor. The feasibility of employing this system as a sustainable low cost and low maintenance treatment alternative at the Williams Brothers abandoned mine site to ensure that drainage effluent will meet water quality objectives showed promise. However, long-term monitoring would be required to demonstrate and ensure their long-term effectiveness.

Issues in using Land Use Capability class to set nitrogen leaching limits in moisture-deficient areas—a South Island case study

ABSTRACTIn setting catchment nutrient limits aimed at meeting water quality objectives, some regional councils have adopted or are considering a natural capital approach to set farm-scale nutrient discharge allowances, whereby soils with a higher natural capital are given a higher discharge allowance. Land Use Capability (LUC) classes have been adopted as a proxy for natural capital. We examine the suitability of LUC for this purpose and identify issues that should be considered when using LUC in the context of a natural-capital-based approach to set nutrient limits, particularly in moisture-deficient areas where irrigation is becoming a major management tool, such as in Canterbury. The main issues are that LUC classes 1–4 are assessed on arable suitability not pastoral suitability, the high variability of pastoral productivity within an LUC class, and the limited correlation of LUC class with nitrogen losses. We propose some modifications to the LUC-based approach to address these issues.

Review of Alternative Management Options of Vegetable Crop Residues to Reduce Nitrate Leaching in Intensive Vegetable Rotations

Vegetable crop residues take a particular position relative to arable crops due to often large amounts of biomass with a N content up to 200 kg N ha−1 left behind on the field. An important amount of vegetable crops are harvested during late autumn and despite decreasing soil temperatures during autumn, high rates of N mineralization and nitrification still occur. Vegetable crop residues may lead to considerable N losses through leaching during winter and pose a threat to meeting water quality objectives. However, at the same time vegetable crop residues are a vital link in closing the nutrient and organic matter cycle of soils. Appropriate and sustainable management is needed to harness the full potential of vegetable crop residues. Two fundamentally different crop residue management strategies to reduce N losses during winter in intensive vegetable rotations are reviewed, namely (i) on-field management options and modifications to crop rotations and (ii) removal of crop residues, followed by a useful and profitable application.

The use of passive treatment alternatives for the mitigation of acidic drainage at the Williams Brother mine, California: Bench-scale study

Abstract The aim of the study was to evaluate passive treatment system alternatives to mitigate acid mine drainage (AMD) characterized by low SO 4 2 - and metal concentrations associated with adit drainage at the Williams Brothers Mine located in the Sierra National Forest, California. Surface water from the site drains into the San Joaquin River Basin and a goal of this study was to mitigate AMD to meet water quality objectives for the San Joaquin River Basin. Effluent sampling from the opening of the lowermost adit identified (AMD) characterized by a pH of 3.90, average SO 4 2 - concentration of 101 mg/L and relatively low average metal concentrations of 4.60, 0.074, 0.047 and 0.133 mg/L for Fe, Cu, Ni and Zn, respectively. The bench-scale study involved the testing of three passive treatment systems: (1) a peat biofilter followed by an anoxic limestone drain (ALD); (2) a SO 4 2 - -reducing bacteria (SRB) bioreactor followed by an ALD; and (3) a single SRB bioreactor. Synthetic AMD was produced to represent the AMD characteristics observed at the site. The peat–ALD system efficiently increased the pH of the effluent to an average of 6.95. Metals were reduced to average concentrations of 0.06, 0.008, 0.013 and 0.057 mg/L, respectively, for Fe, Cu, Ni and Zn. The SRB–ALD system increased the effluent pH to an average of 6.47, decreased SO 4 2 - concentrations to an average of 11.6 mg/L and decreased the concentrations of Fe, Cu, Ni and Zn to averages of 1.04, 0.004, 0.016 and 0.025 mg/L, respectively. The SRB system efficiently increased the pH to an average of 6.56 and decreased SO 4 2 - concentrations to an average of 18.8 mg/L. Metal concentrations for Fe, Cu, Ni and Zn were reduced to 0.63, 0.006, 0.010 and 0.027 mg/L, respectively. The peat–ALD and SRB systems were capable of increasing the pH of the AMD to 6.5 to meet water quality objectives. The peat–ALD system was capable of removing Fe and Cu to below water quality objectives, however, removal of other metals was insufficient. The SRB containing systems were incapable of removing Fe to water quality objectives, while sufficient removal of Cu, Ni and Zn was attained. From these results, the most effective treatment system would incorporate a peat biofilter, for Fe and Cu removal and a SRB bioreactor for Cu, Ni and Zn removal. The results of this study demonstrate that passive treatment mitigation of AMD can best be accomplished via the use of a combined treatment system that incorporates a peat biofilter, SRB bioreactor and anoxic limestone drain, thereby accomplishing targeted removal of constituents in individual system components.

Case Studies of Dam Removal and TMDLs: Process and Results

Because of its storied history, the Cuyahoga River in Ohio is often used as a measure of progress toward water resource integrity within the United States. The river has shown dramatic chemical/physical water quality improvements but is still not fully attaining water quality goals due to impacts to the river from non-regulated sources. A section of the Clean Water Act entitled Total Maximum Daily Load (TMDL) provides a process to address these impacts. A TMDL report for the Cuyahoga River near Kent, Ohio recommended modification or removal of two dams to restore habitat and meet water quality objectives in the river. In response to the TMDL, the historic Kent dam was modified in 2004 and the Munroe Falls dam located approximately 5 miles downstream from the Kent dam was removed in 2005. The Ohio Environmental Protection Agency sampled fish and macroinvertebrate communities, evaluated habitat, and monitored dissolved oxygen concentrations in the middle section of the Cuyahoga River near Kent. Data showing marked improvements of the fish community less than 1 year after dam modifications in Kent and improved dissolved oxygen concentrations after the Munroe Falls dam removal are presented. This paper will also discuss and contrast methods of interacting with the public and local governments and propose guidance for future projects.

Application of CCME Water Quality Index to Monitor Water Quality: A Case Study of the Mackenzie River Basin, Canada

All six ecosystem initiatives evolved from many years of federal, provincial, First Nation, local government and community attention to the stresses on sensitive habitats and species, air and water quality, and the consequent threats to community livability. This paper assesses water quality aspect for the ecosystem initiatives and employs newly developed Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI) which provides a convenient mean of summarizing complex water quality data that can be easily understood by the public, water distributors, planners, managers and policy makers. The CCME WQI incorporates three elements: Scope - the number of water quality parameters (variables) not meeting water quality objectives (F(1)); Frequency - the number of times the objectives are not met (F(2)); and Amplitude. the extent to which the objectives are not met (F(3)). The index produces a number between 0 (worst) to 100 (best) to reflect the water quality. This study evaluates water quality of the Mackenzie - Great Bear sub-basin by employing two modes of objective functions (threshold values): one based on the CCME water quality guidelines and the other based on site-specific values that were determined by the statistical analysis of the historical data base. Results suggest that the water quality of the Mackenzie-Great Bear sub-basin is impacted by high turbidity and total (mostly particulate) trace metals due to high suspended sediment loads during the open water season. Comments are also provided on water quality and human health issues in the Mackenzie basin based on the findings and the usefulness of CCME water quality guidelines and site specific values.

Key success factors in an ASR scheme

Wessex Water in conjunction with CH2 MHill and the British Geological Survey (BGS) has recently completed a major 3 year investigation into the resource potential of Aquifer Storage and Recovery (ASR) in a confined Chalk aquifer. The main part of the investigation followed the approach that has been successfully adopted in developing many ASR schemes in America in which the aim is to create a reservoir of potable water within a non-potable aquifer. In the Wessex Water case study it was found that elevated levels of fluoride prevented a potable reservoir being created, even after a 2 year programme of injection and recovery cycles. In terms of strict water quality criteria ASR was deemed unsuccessful. However when modelling the hydraulic response of the aquifer it confirmed that an ASR abstraction regime created little or no environmental impact and offered significant environmental advantages when compared with conventional groundwater development. It has always been assumed that ASR schemes have this inherent environmental advantage, but it is believed that this is the first time these benefits have been clearly demonstrated at a specific ASR site. The lesson that can be drawn from these results is that environmental acceptability is fundamental to the success of an ASR scheme whereas securing water quality improvements is more likely to be important in determining scheme cost effectiveness. At a time when finding environmentally acceptable resource schemes is becoming increasingly difficult, ASR has a potentially significant advantage over alternative forms of resource development. However, the authors are concerned that because most case studies in England are focusing on water quality issues, these will be viewed as the key success factors for ASR and that its inherent environmental advantages will be overlooked. With most case studies reporting difficulties in meeting water quality objectives this could lead to the general perception that ASR is unlikely to be successful in this country and result in potentially beneficial applications being rejected or not even considered.

REAL‐TIME MANAGEMENT OF WATER QUALITY IN THE SAN JOAQUIN RWER BASIN, CALIFORNIA1

ABSTRACT: In the San Joaquin River Basin, California, a realtime water quality forecasting model was developed to help improve the management of saline agricultural and wetland drainage to meet water quality objectives. Predicted salt loads from the water quality forecasting model, SJRIODAY, were consistently within ± 11 percent of actual, within ± 14 percent for seven‐day forecasts, and within ± 26 percent for 14‐day forecasts for the 16‐ month trial period. When the 48 days dominated by rainfall/runoff events were eliminated from the data set, the error bar decreased to ± 9 percent for the model and ± 11 percent and ± 17 percent for the seven‐day and 14‐day forecasts, respectively. Constraints on the use of the model for salinity management on the San Joaquin River include the number of entities that control or influence water quality and the lack of a centralized authority to direct their activities. The lack of real‐time monitoring sensors for other primary constituents of concern, such as selenium and boron, limits the application of the model to salinity at the present time. A case study describes wetland drainage releases scheduled to coincide with high river flows and significant river assimilative capacity for salt loads.

A demonstration of the benefits of integrated wastewater planning for controlling transient pollution

The Urban Pollution Management (UPM) Research Programme has been the UK Water Industry's response to the need to limit the risk of transient pollution of receiving waters resulting from intermittent discharges, such as combined sewer overflows. Demonstrating that the UPM tools, such as MOSQITO, STOAT and MIKE 11, can be used to produce cost-effective and reliable solutions to practical problems is considered to be a major element in promoting the benefits of the UPM Procedure approach by eliminating the uncertainty of water quality impact associated with more traditional approaches. A demonstration of the full UPM Procedure for inland situations has been carried out in the city of Derby, in the UK, where high levels of investment are planned for both sewerage and sewage treatment.Detailed simulation models were calibrated and verified and then used with the simplified pollution modelling tool, SIMPOL, to evaluate the integrated environmental impact of a possible sewerage upgrading option. The results indicated that this option would meet wet-weather water quality, requirements at a reduced cost compared to alternatives derived from traditional planning procedures which had a high degree of uncertainty in meeting water quality objectives.

A demonstration of the benefits of integrated wastewater planning for controlling transient pollution

The Urban Pollution Management (UPM) Research Programme has been the UK Water Industry's response to the need to limit the risk of transient pollution of receiving waters resulting from intermittent discharges, such as combined sewer overflows. Demonstrating that the UPM tools, such as MOSQITO, STOAT and MIKE 11, can be used to produce cost-effective and reliable solutions to practical problems is considered to be a major element in promoting the benefits of the UPM Procedure approach by eliminating the uncertainty of water quality impact associated with more traditional approaches. A demonstration of the full UPM Procedure for inland situations has been carried out in the city of Derby, in the UK, where high levels of investment are planned for both sewerage and sewage treatment. Detailed simulation models were calibrated and verified and then used with the simplified pollution modelling tool, SIMPOL, to evaluate the integrated environmental impact of a possible sewerage upgrading option. The results indicated that this option would meet wet-weather water quality requirements at a reduced cost compared to alternatives derived from traditional planning procedures which had a high degree of uncertainty in meeting water quality objectives.

A MICROCOMPUTER PROGRAM FOR SELECTING AND OPTIMIZING ACID LAKE RENOVATION TECHNIQUES

ABSTRACT In support of the U.S. Fish and Wildlife Service's Acid Precipitation Mitigation Program, International Science & Technology, Inc., and its subcontractors, AquaComp, Inc. and Svenska IS&T, developed a microcomputer-based decision model to assist water resource managers in selecting the most effective chemical neutralization strategy for renovating acid-stressed lakes and streams. The program can be used to establish proper dosages for a neutralization agent such as aglime through a dose calculation/dissolution subroutine. In addition, the program can assist in the selection of the most appropriate chemical agent, grain size (for neutralization agent), application technique, and reapplication rates to optimize costs and effectiveness for treating a particular system. The program also has subroutines that address dose calculations and effectiveness in meeting water quality objectives.

Simulation of Recent and Projected Total Phosphorus Trends in Lake Ontario

Recent trends (1965 through 1978) of total phosphorus were analyzed with a time-variable, nutrient budget model of Lake Ontario. Future conditions were also simulated to estimate the effect of anticipated control measures on the lake's water quality. The analysis suggests that recent improvements in Lake Ontario's total phosphorus concentration are attributable to point source reductions due to detergent limitations and waste treatment by the Province of Ontario and the State of New York. Projections show that present point source controls will maintain the lake at the upper level of mesotrophy (15-20 μgP/L) to the year 2000, whereas the absence of controls would result in eutrophy (∼30 μgP/L). Further indications are that some diffuse source reduction may be required if oligotrophy (<10 μgP/L) is the ultimate goal and that Lake Ontario's fate is closely related to that of Lake Erie. An attempt is made to assess the effect of model uncertainty and phosphorus availability on the projections. In general, the inclusion of uncertainty indicates that more stringent load reductions will be needed to meet water quality objectives with greater than 50% certainty. Inclusion of availability tends to improve prospects for lake restoration and to enhance point as opposed to diffuse source controls.