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Effect of geospatial data resolution in watershed modeling for integrated watershed management

Philip Adalikwu, Department of Civil and Environmental Engineering, SDSU

Studies show that the use of geospatial data from multiple sources and of different resolutions make it difficult to utilize simulation results for meaningful watershed management decisions. The objective of this study was to determine the effect of data resolution on runoff volume (Q), peak discharge (QP) and time to peak (Tp) predictions, at the outlet of Indian Creek watershed (6.487 square miles) located in Perkins County, South ��ֱ����, using US Army Corps of Engineering Hydrologic Engineering Centre Hydrologic Modeling System (HEC-HMS). Perkins County is on the northern edge of South ��ֱ����, with a terrain of semi-arid rolling hills carved by drainage creeks. Its total area of 2,890 square miles is made up of 2,870 square miles of land and 20 square miles of water. Methodology for the study consisted of geoprocessing (resizing) of all input data to the same resolution, overlaying of digital elevation model (DEM) with other data such as land use/land cover, impervious percentage, streams and curve number (CN) grids, using GeoHMS extension in ArcMap 10.4 to build models for resolutions of 10mx10m to 100mx100m, and simulation of models using HEC-HMS. Preliminary results showed that while runoff volume (Q) and peak discharge (Qp) remained constant and fairly constant for all data resolutions respectively, peak discharge (Qp) increased proportionally for other resolutions, with fluctuations between 40mx40m and 80mx80m, confirming results of previous studies. Therefore, for proper and effective watershed management, it is important for a watershed manager to know that data resolution affect simulation outcomes when making management decisions.

Keywords: watershed management, geospatial data

Hydrologic performance of a residential rain garden in South ��ֱ����

Farhana Akhter, Department of Agricultural and Biosystems Engineering, SDSU

Currently, more than half of the world population lives in an urban area, and the growth rate of urbanized area is increasing. Urbanization changes the hydrology by creating impervious land cover. Impervious surfaces do not allow stormwater to infiltrate into the ground and causes excess stormwater runoff. In undisturbed landscapes, the majority of precipitation becomes infiltration or evapotranspiration. Flooding, stream bank erosion and water quality degradation are common impacts of watershed disturbance. Low Impact Development (LID), also called green infrastructure (GI), is a stormwater management practice that helps to reduce runoff volume and peak flow, to recharge groundwater and to improve water quality by recreating natural hydrologic processes. Rain gardens are one of the LID/GI techniques and consist of a shallow depression in the landscape that catches, stores and infiltrates stormwater.

A rain garden was constructed in the backyard of a residence in Sioux Falls. Runoff is routed into the rain garden from the building roof. Four 0.4 foot HS-flumes and pressure transducers were installed at the inlet and the outlet of the rain garden to measure the flow volume, and two pressure transducers are installed in the middle of the rain garden to measure ponding depth. The volume of stormwater runoff captured by this rain garden is being measured to evaluate the hydrologic effectiveness of a residential rain garden as an urban stormwater management practice in South ��ֱ����.

Hydrological Models for Rainfall-runoff in Arid Regions: A Literature Review

Ali Alsubeai Department of Civil and Environmental Engineering, SDSU

Hydrological models were created to work with limited input parameters, so they are not necessarily valid unless they have been tested in different situations. The majority of models were created for humid regions which receive high amounts of precipitation compared to arid regions as well as other differences. For instant, vegetation cover is extensive in humid areas compared to arid areas. In addition, there are very intense rainfall events that occur during the year which causes runoff in both humid and arid regions. Moreover, soil characteristics affect infiltration rate such as variations in layer depths, and accessibility to be storage. The objective of this paper is to present results of a literature review and analyses of hydrological models used in arid regions. Furthermore, 13 models were reviewed in different countries, Saudi Arabia, China, Jordan, Tanzania and Libya where the arid climate is prevalent. All of the models were developed for humid regions. Results will be presented for the models studied and typical modifications implemented to use the model in arid regions.

Simulating the influence of integrated crop-livestock systems and future climate scenarios on water yield at watershed scale

Arun Bawa, Department of Agronomy, Horticulture and Plant Science, SDSU

The watershed hydrology is mainly driven by different factors viz., land cover, soil type, landscape and climate. Understanding the impact of these hydrology governing parameters can help in better planning and management of hydrological resources. Among these determinant factors, land cover and climate are most dynamic in nature. Agricultural practice like integrated crop-livestock (ICL) system is being widely promoted as eco-friendly practices. However, the potential effects of the ICL system on hydrological cycles is not well evaluated yet. Thus, we simulated the potential impacts of ICL system and future climate scenarios on water yield and its hydrological components using Soil and Water Assessment Tool (SWAT) hydrological model. In this study, the conventional ICL system (corn-soybean with corn residue grazing) was applied with CMIP5 future climate scenarios over agricultural land in the Skunk Creek watershed. Total 66 scenarios were simulated using four representative concentration pathways for projected climate scenarios from four general circulation models considering two future time periods i.e. Near future(NF; 2021–2050) and far future(FF;2069–2099). Modeling results showed a significant reduction in water yield (6.6%) and surface runoff (15%) under ICL system over a long-term period simulation (30 years) while climate changes scenarios induced higher water yield (7-37% for NF period and 15-66% for FF period) and surface runoff (0-18.5% for NF period and 8.5-12% for FF period). Long term ICL system with future climate scenarios have resulted in reducing the climate change impacts on hydrological components by reducing the surface runoff. The combined effect of long-term ICL system adoption and climate changes would result in 4-34% increase in water yield for NF and 16-63% for FF. Overall, this study suggests new watershed-scale benefits of ICL systems with important hydrological implications that might be of interest for agricultural watershed planners.

A Green Solution for a Gray Project

Gabe Heller, School of Design, SDSU

Landscape architecture students at SDSU recently investigated green stormwater management practices for a new parking lot proposed at the Brookings Government Center. Specifically, the design problem required students to provide a minimum of 40 parking spaces, a small plaza and green infrastructure strategies to detain and infiltrate the first one-inch (1”) of rainfall from new paved areas and manage peak flows from the 5-year storm event. The design solution required that students integrate all practices into the available 0.75 acre site and provide hydrologic calculations confirming stormwater capture.

This poster will present a proposed design for the project site. The solution provides required parking and a small plaza. Stormwater has been managed using porous asphalt and bioretention. The poster will include an illustrated site plan, graphic renderings, grading and drainage information, as well as HydroCAD calculations used to size and confirm effectiveness of proposed green infrastructure practices.

A study of estimation techniques for filling in missing precipitation data values

Ghaem Hooshyari, Civil and Environmental Engineering Department, SDSU

Precipitation plays a significant role in agriculture and it is a major area in climatological studies. Studying about precipitation is important in (1) statistical modeling and forecasting of precipitation (2) identifying precipitation characteristics; occurrence and temporal and spatial variability and (3) resolving the problems such as floods, droughts, and landslides. The goal of this research was to analyze the precipitation record for Brookings, SD and to develop the techniques that are reliable to estimate the missing data. For this purpose, statistical analyses were performed using the monthly precipitation data from the High Plains Regional Climate Center (HPRCC) for the monthly and seasonal periods. Precipitation data between years 1893-2019 were used for the study to develop the climate periods for ‘Wet’, ‘Very wet’, ‘Mean’, ‘Dry’ and ‘Very dry’. Correlations between Brookings, SD, data and surrounding location data records were made for daily precipitation values. Correlations between stations varied depending on the month and season of the data compared. The results of this study provides information on different factors that may affect traditional estimation methods used to fill in missing precipitation records.

Removal of E. coli From Stormwater Using Filtration with Recycled Steel Media

Blake Jorgensen, Water and Environmental Engineering Research Center, SDSU

Contaminated stormwater runoff is a major contributing factor to the impairment of lakes, rivers and other bodies of water. Often stormwater will contain bacteria, phosphorous, metals and other contaminants which can have adverse effects on surface water quality and public health. In South ��ֱ����, many rivers and lakes are impaired by high levels of E. coli transported by stormwater runoff generated from highways, urban areas and agricultural settings. There is critical need to develop practical technologies to reduce E. coli contamination in stormwater runoff. Recent studies have shown that recycled steel byproducts are an effective adsorption material for E. coli removal from water. The objective of this study was to determine the E. coli removal efficiency of a pilot-scale steel byproduct filter installed in a stormwater detention pond. The effect of the steel byproduct filter on phosphate removal was also evaluated.

An open-top, rectangular filter structure was placed in front of an inlet leading to a stormwater detention pond located in Brookings, SD. Recycled steel chips and steel slag were used as filter media for this study. The filter media included 25% large slag (4-9.4 mm), 25% small slag (2-4 mm), 25% large steel chips (4-9.4 mm) and 25% small steel chips (2-4 mm). Filter influent and effluent samples were collected during four stormwater events from June to August, 2019. The E. coli removal by the filter ranged from 44 to 88%, with an average removal efficiency of 69%. The average phosphate removal by the filter was approximately 49%. The results of this pilot-scale study suggest that recycled steel byproduct filtration is an effective E. coli removal technology for stormwater treatment.

Nutrient Removal from Agricultural Subsurface Drainage Using Different Pairing Configurations of Woodchips and Steel Chips

Abdoul Aziz Kouanda, Department of Civil and Environmental Engineering, SDSU

Woodchips bioreactors have been used as a method for removing nitrate from agricultural subsurface drainage water. Recent studies also suggest that subsurface drainage is an important pathway for the transport of phosphate from agricultural land to surface water. Therefore, technologies are needed to control both nitrate and phosphate in subsurface drainage. Steel byproduct filters have been proposed to be used in conjunction with woodchip bioreactors to remove nitrate and phosphate from subsurface drainage water. The objective of this study was to determine the impact of different pairing configurations of woodchips and steel byproducts on treatment performance. Three different pairing configurations were evaluated in this project including woodchips followed by steel chips, steel chips followed by woodchips and mixed woodchips/steel chips. Laboratory column rectors were built based on the three configurations and their nutriment removal capacities were evaluated.

The three-column reactors were used to treat simulated drainage water with 30 mg N/L nitrate and 10 mg P/L phosphate at a fixed hydraulic retention time of 12 hours for three months. The woodchips to steel chips volume ratio was 11:1. The results showed that woodchips+steel chips, steel chips+woodchips and mixed woodchips/steel chips reactors achieved average nitrate removal percentage of 52.1, 63.4 and 63.6% respectively. The average phosphate removal percentages were 80.5, 82 and 84%, respectively, for three configurations. All three reactors configurations achieved good removal of nitrate and phosphate. The results also showed that woodchips were able to remove dissolved iron whereas steel chips were able to reduce organic carbon concentrations.

Nitrate in Tile-Drain Water Relative to Time and Source of Nitrogen Application in Southwestern Minnesota

Sonia Menegaz, Department of Soil, Water and Climate, University of Minnesota

Nitrogen (N) is the nutrient required in greatest quantity for corn production. Plants are not always able to take up all the N fertilizer and considerable amounts can be lost. Nitrogen lost through leaching in agricultural tile-drainage systems can create environmental degradation. Our goals were to (1) quantify the effects of N fertilizer sources and application timing on NO3-N concentration and load in tile-drain water, and (2) quantify nitrogen use efficiency through corn N uptake and grain yield. This study was conducted in Lamberton, MN in a continuous corn (Zea mays. L.) system between 2015 and 2017 with four treatments organized in a randomized complete block design with four replications. The N rate applied in the plots was 180 lb/ac, which is similar to what farmers usually apply in southwestern MN. The application was done either as a single pre-plant or split applied with 60 lb N/ac at pre-plant and 120 lb. N/ac at V4 development stage. The pre-plant applications consisted of urea and ESN broadcast and incorporated with tillage. The split application was done with Agrotain. Numerically, treatments containing ESN tended to yield more than other treatments. Preliminary results (2015-2017) showed that ESN treatment produced less nitrate load (11.4 kg/ha) when compared with the split urea treatment (18.6 kg/ha). Numerically, pre-plant treatments produced less annual nitrate load (13.85 kg/ha) than split application treatments (17.4 kg/ha), on average. The average nitrate load for ESN treatments (13.8 kg/ha) was numerically lower than the treatments with only urea (17.45 kg/ha) consistently every year.

Nanomaterials based electrochemical sensor for enhanced detection of heavy metal in water

Md Tawabur Rahman, Department of Electrical Engineering and Computer Science, SDSU

A highly sensitive and selective electrochemical sensor for detecting mercury (Hg2+) in aqueous media was demonstrated. Graphene oxide (GO) and silver nanowire (AgNW) nanocomposites modified platinum electrode has been applied to determine Hg2+ using square wave anodic stripping voltammetry. Enhanced sensing of Hg2+ was obtained due to the synergistic effect of GO and conductive AgNW. Under the optimum experimental conditions, the sensor showed a high sensitivity of ~ 0.29 µA/nM and linear response in the range of 1 - 70 nM toward Hg2+. The detection limit of 0.1 nM was achieved, which is significantly less than the acceptable limit defined by the World Health Organization. The sensor has excellent selective response to Hg2+ against other interfering heavy metal ions such as Pb2+, Cd2+, Cu2+, Na+, Ag+, etc. Besides, the sensor showed a high repeatability and reproducibility. The sensor is employed for the detection of Hg2+ in tap water samples with high accuracy and recovery, suggesting it has potential for on-site monitoring of Hg2+ in water.

Fate and transport of bioplastic in water environment

Sepideh Sadeghi, Department of Civil and Environmental Engineering, SDSU

Production of plastics has increased in past three decades. Plastics are widely used in food industry and agricultural fields since they are light weighted, durable, corrosion resistant and inexpensive. Waste of plastics has challenged society with the problem of micro plastic accumulation in the environment which may have adverse impacts on the environment. One solution proposed is to use bioplastics (biodegradable polymers), such as polylactic acid (PLA) which is made from corn-based cornstarch, as a substitute for conventional polymers to reduce accumulated plastic waste, however biodegradability is a material property occurring under certain environmental conditions and therefore requires systematic study. The goal of this research was to quantify the degradability of PLA in the agitated and unagitated water environment under controlled conditions. Specifically, the influence of different temperature in 100 % humidity on the degradation of ground PLA were studied. Laboratory experiments were conducted on agitated and unagitated water including ground PLA in different sizes: 2.36 mm, 2 mm and 1.18 mm for one month, and degradation changes in PLA were assessed based on the changes in organic carbon content in the solution. The impact of PLA degradation on pH and conductivity was also investigated. According to the results, ground PLA in the size of 2.36 mm showed the highest organic carbon release in 40℃ in sterilized water after one month in the agitated condition. The pH was decreased from 9 to 6 after one month, however conductivity was increased from 16 to 64 µS/cm. The DOC decreased ~ 17% and ~ 81% in 40℃ and 20℃, respectively, after one month in the surface water. Microbial communities’ variation in surface water with the presence of bioplastics nanoparticles was also investigated using EcoPlate. The results showed that surface water microbial community was changed in the presence of PLA.

Keywords: Biodegradation, PLA, biodegradable plastics, EcoPlate

Next-generation wastewater treatment and reuse technology using a three-staged bio-electrochemical module

Bhuvan Vemuri, Department of Civil and Environmental Engineering, South ��ֱ���� School of Mines and Technology

Here we present a comprehensive energy analysis of novel bio-electrochemical treatment train that integrates three-stage processes, thermophilic fermentation (Stage I), microbial fuel cell (Stage II), and ultra-filtration processes (Stage III). The first stage uses thermophiles isolated initially from cattle manure for generating hydrogen using chemical oxygen demand from wastewater. The first stage reduced the COD from ~ 200 mg/L to 53 mg/L. Stage II further reduced the COD to the limits defined by the NPDES permit. Stage III served as a polishing unit to eliminate remaining COD, microbial debris, foulants and a range of metals. A 30-kDa poly (ether sulfone) ultrafiltration membrane (Microdyn-Nadir® UH030 P) used in stage III was rendered hydrophilic and foulants-resistant using mussel-inspired dopamine chemistry. We will present a net energy analysis of the three-staged processes (jointly termed as a bioelectrochemical module) and compare the energy performance with contemporary activated sludge process. The enhanced net energy gain of the module is primarily due to its ability to minimize oxygen and pumping requirements.