Developing a Numerical Water Quality Model for Brewster Lake

The purpose of this research study was to develop an advanced two-dimensional process-oriented numerical water quality model for Brewster Lake that incorporates the physical, chemical, and biological interactions that occur within the lake. The study included measuring and obtaining the basic physical, chemical, and biological characteristics of the lake to develop the model and appropriate initial and boundary conditions. Two rounds of measurements, one in the beginning of June and one at the end of July 2013, of the physical and chemical variables were conducted and were used to develop and calibrate the model. A hydrodynamic analysis of the lake\u27s watershed was completed using a mass balance approach over water. A set of process-oriented water quality mathematical equations that incorporates the water chemical and biological interactions was developed. The finite element solution will result in predicted values for the lake\u27s water quality parameters as a function of time and varying environmental conditions. It is anticipated that the results of this computer modeling will aid the Pierce Cedar Creek Institute staff in decision-making related to the management and planning of Brewster Lake and its watershed

Impact of Autumn Olive Nitrogen-Fixation on Groundwater Nitrate Concentration

Autumn olive (Elaeagnus umbellata) is an exotic and invasive species that was used extensively as an erosion control plant along many highways in the Midwestern United States during the last century. Due to its invasive and strong nitrogen-fixing abilities, it aggressively spread outside its intended use area. Unfortunately, control management programs by many organizations have failed to control its spread. Currently, it exists in dense patches over vast areas in the Midwest. A by-product of its nitrogen-fixing is nitrate. Nitrate is regulated in drinking water for its known toxicity to human and animal infants. This study assesses the leaching of nitrate from autumn olive infested areas into its surrounding environment. Soil and groundwater samples were collected from areas infested with autumn olive and from paired nearby grass plots in Indiana and Michigan between 2009 and 2014. The samples were analyzed for nitrate, ammonia, and total nitrogen in addition to other relevant chemical and physical soil and water parameters.A matched pairs t-test indicates that the concentration of nitrate is significantly higher (p-value=0.0002) in the soil and groundwater beneath the autumn olive infested areas compared to their control areas. The nitrate concentrations in soil water of many infested areas exceeded the EPA’s MCL of 10 mg/L and were over ten times higher compared to their control areas. The data also showed varying seasonal nitrate leaching levels. Read More: http://ascelibrary.org/doi/abs/10.1061/9780784479865.00

An Iron-Enhanced Rain Garden for Dissolved Phosphorus Removal

As a stormwater management technique, rain gardens can reduce runoff volume and retain contaminants such as metals found in urban stormwater runoff. Due to organic material in rain gardens such as plants, mulch, and compost, however, rain gardens have been shown to release dissolved phosphorus, which is typically targeted for removal from stormwater. As a result, rain gardens can act as a source of dissolved phosphorus and cause a corresponding increase in the dissolved phosphorus concentration in runoff. This project assesses the performance of an iron-enhanced rain garden with regards to its ability to retain dissolved phosphorus. Studies have shown that iron-enhanced sand filtration has the ability to remove over 90% of dissolved phosphorus from stormwater runoff. A new rain garden design incorporating a layer of sand mixed with iron shavings at 5% (by weight) beneath typical rain garden media was tested under laboratory conditions for its ability to retain dissolved phosphorus. The performance was compared to a control rain garden that contained a layer of only sand beneath typical rain garden media. Preliminary results indicated that the iron-enhanced rain garden consistently retained approximately 90% or more of the dissolved phosphorus load after more than 61 m of water had infiltrated. The control rain garden initially retained over 50% of the dissolved phosphorus load. However, after the same depth of infiltrated water, dissolved phosphorus retention dropped significantly and ultimately became negative

Quantifying Nitrate Leaching from Autumn Olive into Groundwater

Elaeagnus umbellata (Autumn Olive) was introduced to the United States in 1830 as a means of fast growing wildlife habitats and for erosion control. The Asian native plant is now an invasive species that disturbs the plants that are native to the United States. The autumn olive has nitrogen-fixing roots which allow the plant to grow in a variety of soil types, making it all the more invasive. When there is a heavy rainfall, highly mobile nitrate residual from the plant roots may be washed through the soil and enter the groundwater. Nitrate is the form of nitrogen that primarily affects groundwater and if untreated is toxic to children under a year old and small animals. A farm containing a large population of autumn olive plants was used as a research site for nitrate testing. In the fall of 2014, 16 lysimeters were installed to collect groundwater; eight placed near an autumn olive plant as samples, and eight placed away from the plants in a neutral area as controls. Groundwater was collected from each of the 16 lysimeters weekly until the first snowfall. The water was tested for nitrite, nitrate, and total nitrogen within 24 hours of being retrieved. Potassium and hardness testing was also conducted. Current results show that nitrate levels are higher near the autumn olive plants compared to the controlled locations. The results of the research have not yet been completed due the continuing collection from the lysimeters into the spring