Predicing Ecological Effects of Watershed-Wide Rain Garden Implementation Using a Low-Cost Methodology

Stormwater control measures (SCMs) have been employed to mitigate peak flows and pollutants ssociated with watershed urbanization. Downstream ecological effects caused by the implementation of SCMs are largely unknown, especially at the watershed scale. Knowledge of these effects could help with setting goals for and targeting locations of local restoration efforts. Unfortunately, studies such as these typically require a high level of time and effort for the investigating party, of which resources are often limited. This study proposes a low-cost investigation method for the prediction of ecological effects on the watershed scale with the implementation of rain garden systems by using publicly available data and software. For demonstration purposes, a typical urban watershed was modeled using Storm Water Management Model (SWMM) 5.0. Forty-five models were developed in which the percent impervious area was varied 3 to 80%, and the fraction of rain gardens implemented with respect to the number of structures was varied from to 100%. The river chub fish (Nocomis micropogon) and its congeners (Nocomis spp.) were chosen as ecological indicators, as they are considered to be keystone species through interspecific nesting association. Depth and velocity criteria for successful nest building locations of the river chub were determined; these criteria can then be applied to many other watersheds. In this study, both base flow conditions and a typical summer storm event (1.3 cm, 6 h duration) were evaluated. During the simulated storm, nest-building locations were not affected in the 3 and 5% impervious cover models. Nest destruction was found to occur in approximately 54% of the original nest building sites for the 9% and 10% impervious areas. Nearly all of the nest-building locations were uninhabitable for impervious areas 20% and greater. Rain garden implementation significantly improved river chub habitat in the simulation, with greatest marginal benefit at lower levels of implementation

Evaluation of the long term impacts of an infiltration BMP

Proceedings of the Seventh International Conference on Hydroscience and Engineering, Philadelphia, PA, September 2006. http://hdl.handle.net/1860/732The natural hydrologic cycle is severely disrupted by development because the water that used to infiltrate into the ground is now running off into nearby streams. The negative impact of development on streams includes increased stream bank erosion, pollutant levels, and decreased base flow. Best management practices (BMPs) are recommended by regulatory agencies because they can mitigate peak flow, provide treatment, and partially restore the natural hydrologic cycle. BMP is a broad term used to describe a host of structures and activities; they are classified as structural (e.g. infiltration basin) or non structural (e.g. street cleaning). While infiltration BMPs are gaining acceptance, there is a concern that infiltrating stormwater has solved one problem by improving stream quality, but has caused another by contaminating the groundwater. To date, there have not been many opportunities to study the long term effects of infiltration. However, two 85 to 100 year old infiltration pits were discovered on the campus of Villanova University. Soil samples were collected from these pits and were tested for copper. Copper was selected based on the contaminants seen in the stormwater at other Villanova BMP sites. One of the pits has low infiltration rates and a plan to restore its infiltration capacity is described. This restored infiltration pit will serve as a permanent demonstration and research site, joining a collection of BMPs at Villanova University

Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

Predicting Ecological Effects of Watershed-Wide Rain Garden Implementation Using a Low-Cost Methodology

Stormwater control measures (SCMs) have been employed to mitigate peak flows and pollutants associated with watershed urbanization. Downstream ecological effects caused by the implementation of SCMs are largely unknown, especially at the watershed scale. Knowledge of these effects could help with setting goals for and targeting locations of local restoration efforts. Unfortunately, studies such as these typically require a high level of time and effort for the investigating party, of which resources are often limited. This study proposes a low-cost investigation method for the prediction of ecological effects on the watershed scale with the implementation of rain garden systems by using publicly available data and software. For demonstration purposes, a typical urban watershed was modeled using Storm Water Management Model (SWMM) 5.0. Forty-five models were developed in which the percent impervious area was varied 3 to 80%, and the fraction of rain gardens implemented with respect to the number of structures was varied from to 100%. The river chub fish (Nocomis micropogon) and its congeners (Nocomis spp.) were chosen as ecological indicators, as they are considered to be keystone species through interspecific nesting association. Depth and velocity criteria for successful nest building locations of the river chub were determined; these criteria can then be applied to many other watersheds. In this study, both base flow conditions and a typical summer storm event (1.3 cm, 6 h duration) were evaluated. During the simulated storm, nest-building locations were not affected in the 3 and 5% impervious cover models. Nest destruction was found to occur in approximately 54% of the original nest building sites for the 9% and 10% impervious areas. Nearly all of the nest-building locations were uninhabitable for impervious areas 20% and greater. Rain garden implementation significantly improved river chub habitat in the simulation, with greatest marginal benefit at lower levels of implementation