Brajesh Gautam 2004

Brajesh Gautam (M.S. Candidate) areas of research interest are wet weather flow modeling and urban stormwater runoff quantity and quality analysis. For my current work, I have been using a multi-step approach consisting of sampling and model simulation to study the effect of land use and other drainage area properties on the runoff flowrate and quality. The results from my analysis have been implemented in the Red River Total Maximum Daily Load (TMDL) report. Degree: 2001 – B.S. in Civil Engineering, Institute of Engineering, Nepal

Fellow: Brajesh Gautam, Department of Civil Engineering
Advisor: Dr. Wei Lin, Associate Professor, Department of Civil Engineering, NDSU
Advisory Committee: Dr. G Padmanabhan, Dr. Eakalak Khan, Dr. Bernhardt Saini-EidukatDegree
Progress: M.S. in Environmental Engineering expected in December 2005.

Analysis and Model Simulation of Stormwater Runoff -- A Study of Land Use and System Design on Discharge Flow Rates and Water Quality

Description of Critical Water Problem

In a 1988 report to the Congress, USEPA stated that urban runoff in the U.S.A is the fourth most extensive cause of water quality impairment of rivers, and the third most extensive source of water quality impairment of lakes (USEPA, 1990; Novonty, 1991; Novonty and Olem, 1994).Yields of total suspended solids (TSS), total phosphorus (TP), and total nitrogen (TN) from intensive agriculture and urban areas in the Great Lakes region were 10-100 times greater than from the forested and idle lands (Sonzogani et al.1980).Urban development increases stormwater runoff volumes and pollutant concentrations. Impervious surfaces, such as rooftops, driveways, and roads, reduce infiltration of rainfall and runoff into the ground and degrade runoff quality. Land use and storm sewer system design all have important effects on stormwater runoff quality. BOD5, bacteria and nutrient concentrations in stormwater are typically lower than in raw sanitary wastewater. However, urban stormwater still has relatively high concentrations of bacteria, BOD5, and suspended solids along with high concentrations of many metallic and organic toxicants (Burton, G. Allen et al, 2002).

The Red River is an important resource for water supply and recreational purposes. However, the reach of Red River main stem covering Moorhead, MN and Fargo, ND areas has been identified as impaired for swimming designated use (primary contact recreation) under Section 303(d) of the Clean Water Act (CWA). The main causes contributing to impairment are excessive fecal coliform bacteria and high turbidity. High ammonia concentration in the river is another concern. An analysis of Red River quality data shows that urban runoff is a major source of fecal coliform and suspended solids. Fish kill in this reach of Red River occurred after a storm in August 2003. During the period of fish kill, low dissolved oxygen (DO) was observed in the river. Low flow rate in the river and high BOD concentration in the urban runoff were believed to be the reasons for the low DO and subsequent fish kill.

The impact of urban runoff on the quality of a water body may vary significantly depending upon its existing water quality and the rates at which pollutants are introduced into the system. So we need to study flow of the runoff and major contaminant concentration. The multiple of flow rate and concentration is known as loading rate or simply load. So load of a particular stormwater outfall relates to the impairment of the reach of the receiving water body. Therefore to accurately asses the effect of urban runoff and to propose control measures, load has to be calculated. The first step in the calculation of load is to estimate runoff. Runoff quantity is governed by the hydrological and physical characteristics of the of the drainage area. Simulation models are now days widely used in estimating stormwater flows in urban areas. More advanced models can simulate pollutants concentration in addition to flow and stages. So to find a broader picture of the affect of urban runoff on the Fargo Moorhead reach of Red River, sampling of the runoff and using this data to simulate a model is proposed.

The proposed research will be incorporated and synchronized with other related works going on with the view of analyzing the urban runoff of Fargo-Moorhead area. There is currently study going on to find out the Total Maximum Daily Load (TMDL) for the Fargo-Moorhead reach of the Red River. In this regard samples have been collected by River Keepers, the city of Moorhead and ND Department of Health. A number of samples from different location has been collected and analyzed for fecal coliform analysis and turbidity analysis. The analysis of 2002 data identified that fecal coliform is mainly being discharged from the urban area. The stormwater sampling has been started this year and initial data show high BOD, fecal coliform and turbidity in storm runoff. An initial GIS map of urban reaches of Red river in Fargo – Moorhead area has been developed.

Key Literature

Hydrological features of a basin govern the storm runoff flow rate. If we analyze the classic ‘Rational Formula’ for peak runoff estimates, runoff coefficient, rainfall intensity and basin area are the three governing factors. Runoff coefficient is associated with the land use of a particular basin. Increased land use or Urbanization has important role to play in the change of flow rate. According to (Chow, et al. 1988), major change in flow rates in urban watershed are the result of (i) the increase in the volume of water available for runoff because of the increased impervious cover of provided by parking lots, streets, and roofs, which reduce the amount of infiltration and (ii) changes in hydraulic efficiency associated with artificial channels, curbing, gutters, and storm drainage collection systems increase the velocity of flow and the magnitude of flow peaks. The storm duration intensity is another factor which has to be looked carefully while estimating runoff. Usually high discharge of stormwater from urban area in the United States results from high intensity short duration rainfall like thunderstorm. For reducing the increase of peak runoff from urban areas stormwater detention ponds are commonly employed in new developments. Although most detention ponds are designed for flow rate control, they may improve the water quality as result of sedimentation in the ponds.

For the analysis of contaminant level of the pollutant, field analysis and sampling is needed. Most water quality data consist of concentration of various parameters. Some parameters like pH, conductivity, temperature and dissolved oxygen can be measured in site while other parameters like suspended solids, BOD, COD and bacteria counts require laboratory analysis. The type of pollutant load also tends to relates to the type of land use. For example the bacterial quality of runoff especially from residential area can be poor as a result of animal/bird faeces and wrong connection. (Ellis, J.B; 1985)

The computation of combined effect of flow rate and pollutant concentration requires considerable calculations and judgment, which is why simulation models are finding increasing use. As the water quality measurements are costly and time consuming, it may be preferable to use a mathematical model which is verified by limited local measurements and then applied to the system under consideration to obtain an appreciation of the pollution situation. (Huber, C.W, 1986). All models need to be calibrated for local conditions. Calibration usually involves the collection of initial set of data that is used to modify the model for the local characteristics. Validation is an independent check to ensure that the calibrated model produces predictions within an acceptable error range (Burton, G. Allen et al, 2002).

Simulation models have found increasing use from its initial phase in the early 1970. Some of the most popular and comprehensive models are SWMM (Storm Water Management Model) and STORM (Storage Treatment Overflow Model). A widely used simulation model is SWMM which is developed by EPA. SWMM is capable of simulating the movement of precipitation and pollutants from the surface of the ground pipe and channel networks and storage treatment units to receiving water. (Viessman, W and Lewis, 1998)

As stated earlier, this research will be a collaborative effort with the TMDL study going on the department. The analysis of initial data from TMDL study in Red River has given some surprising results. The time – pollution graphs (pollutographs) of some major contaminants are showing variation as regard to peak load. This result in itself is proving to be a challenge and exciting research opportunity. The urban runoff study as proposed in this research proposal will surely help in understanding these results.

Scope and Objectives

The goal of this proposed research is to determine contaminant loads that are carried by urban runoff to the Red River by field sampling and model simulations. The corresponding objectives to achieve the goal are to:

• Collect samples to determine the flow rates and concentration of major contaminants from selected stormwater outfalls
• Develop hydrographs and contaminant load curves based on the field data
• Study the impact of land use and storm water system design on runoff flow rate and quality
• Determine the pollutant loads from Fargo and Moorhead stormwater outfalls through model simulation

Methods, Procedures, and Facilities

The methodology for this research consists of different level of activities. The procedure to achieve above mentioned objectives will follow a well directed path.

Literature Review and Model Evaluation

Literature review gives the sound base to research work. Journal articles, conference papers give the background information about the related activities going on field. Literature review as regard to this research will consist of collection of information on methods, calculations, sampling procedures required for the study. As simulation of model is important aspect of this research, evaluation of different models will also be done. Study of application, updates, and manuals as regard to the model would help in gaining through knowledge of the model and help in its future simulation.

Site Selection

Site selection as regard to this research consists of selection of land use pattern and corresponding selection of stormwater outfall. Area to be sampled will be selected with the help of the GIS map which is already prepared as part of the TMDL study. Some of the different land use patterns that will be considered are; residential, industrial, agricultural and institutional. The selection would be representative of the ground condition. Accessibility of the outfall will be another governing factor. The coverage area, population data of the drainage are will be found out from field study and concerned authority. To study the effectiveness of detention ponds as quality control measure, the area draining in to the detention pond will be studied separately.

Runoff Flow Rate Measurement and Quality Sampling

As already mentioned, flow rate is the function of hydrological and physical characteristics of the area so reliable measurement of these functions must be insured. Rainfall data will be collected from corresponding gauging station. With these data hydrographs would be generated which would help in accurately predicting runoff magnitudes. Another important hydraulic feature is the discharge through the drainage channels. Manning’s equation will be used to calculate the quantity of the flow. Among input parameters for this equation, slope and channel geometry of outfalls will be collected and pressure transducer will be used to measure the water level. Due consideration will be given while obtaining Manning’s coefficient (n).

For the quality parameters of the runoff, continuous monitoring is possible with the use of multi quality measuring instruments. Currently there are number of quality measuring Sonde instruments available for use. It will be calibrated first then placed in the selected outfall. It would collect continuous which would be downloaded with the help of Data logging system.

Logistic support for this research will be provided by Minnesota Pollution Control Agency (MPCA) and NDSU Civil Engineering Department. Computer and GIS software will be used in NDSU. The advisors and faculty of the Department of Civil Engineering would be consulted during the whole research process.

Model Calibration and Simulation

The gathered hydrological, physical data will be used in calibrating the model. After the calibration the model will be used to derive hydrographs and pollutographs. The simulation will give new insights in the affect of land use on urban runoff quality. The whole research and results would be part of the thesis work. The time for this research is expected to take one and half years. So the results would be available in the summer of 2005.

Anticipated Results and Deliverables

Considering the fact that urban runoff has been identified as a major source of pollution to the receiving water body, there is a growing concern for the analysis of the extent of the problems caused by it and development of a proper management plant suited to the local condition. Hence in this regard this research will help in identifying the level of problem and will provide a better understanding of the urban runoff pollution. A simulated model which would predict runoff load will be one important result of this research.

The main benefits of this research will be that it will provide better understanding of the pollutant concentration of the urban runoff which will eventually lead to the improvement of the quality of the receiving water body, in our case Red River. The result of the study will focus the attention to the critical sections of the urban area, which is contributing more to the pollution of the Red River. Another important aspect of this research is to find out how land use pattern corelates with the urban runoff load. Now day’s detention ponds have found increasing use in stormwater disposal system. Some new areas of the Fargo city have been using them as flood control measures. This research will also test does these ponds act as pollutant control devices or not.

Literature Cited

Burton, G. Allen and Pitt, Robert E: (2002), Stormwater Effects Handbook, A toolbox for Watershed Managers, Scientists, and Engineers, Lewis Publishers

Huber, C.W: (1986) ‘Deterministic Modeling of Urban Runoff Quality’, in H.C Torno, J. Marsalek, and M.Desbordes, (eds), NATO ASI Series, Vol G10, Urban Runoff Pollution, Springler-Verlag, Berlin, Heidelberg, pp. 167-241

Wolfang F Geiger: (1986) ‘Use of Field Data in Urban Drainage Planning’, in H.C Torno, J. Marsalek, and M.Desbordes, (eds), NATO ASI Series, Vol G10, Urban Runoff Pollution, Springler-Verlag, Berlin, Heidelberg, pp. 103-127

Tsihrintzis, Vassilios A. and Hamid, Rizwan :(1997), Modeling and Management of Urban Stormwater Runoff Quality: A Review, Water Resources Management, pp 137- 164

Brezonik, Patrick L. and Stadelmann Teresa H.: (2002), Analysis and predictive models of stormwater runoff volumes, loads, and pollutant concentrations from watersheds in the Twin Cities metropolitan area, Minnesota, USA, Water Research, pp 1743-1757

Viessman, W,and Leiws, G.L., (1996), Introduction to Hydrology, Harper Collins

Novonty, V. and Olem, H: (1994),Water Quality- Prevention, Identification, and Management of Diffuse Pollution, Van Nostrand Reinhold

Sonzogni WC, Chesters G, Coote DR, Jeffs DN, Konard JC, Ostry RC, Robinson JB, Pollution from Land Runoff, (1980), Environ Sci TEchonol, 14(2):148-53

Chow VT, Maidment DR and Mays LW, (1988), Applied Hydrology, McGraw -Hill

Publication

Somayajula, S. M. K.; Gautam, B.; Martin, J.; and Lin. W. (2005) Application of Water Quality Modeling in Red River Fecal Coliform Total Maximum Daily Load (TMDL) Development, Presented at the Second International Water Conference Research and Education in an International Watershed: Implications for Decision Making, April 6-7, Winnipeg, Manitoba, Canada.

Martin., J.; Somayajula, S. M. K.; Gautam B.; Lin, W.; Fredrick, F.; and Ell, M. (2005) Stormwater Sampling and Analysis for Fecal Coliform and Turbidity Total Maximum Daily Load (TMDL) Development, Presented at the Second International Water Conference Research and Education in an International Watershed: Implications for Decision Making, April 6-7, Winnipeg, Manitoba, Canada.

Wei Lin
Civil & Environmental Eng.
Office: Civil/Ind Eng 201D
Telephone: 701-231-6288
Email: wei.lin@ndsu.edu