The thesis work titled "Optimal ecological management practices for controlling sediment and water yield from an urban hill system within the sustainable limit" was carried out by me under the supervision of Prof. Sarma of the Department of Civil Engineering, IIT Guwahati and Prof. Mahanta of the Department of Civil Engineering, IIT Guwahati. In particular, I sincerely thank Dimpal, Mridul, Biswajit and Anjal for their help in the experimental works.
PRIORITIZATION OF DEGRADED WATERSHEDS 36-63
Assessment of Sediment Control Capacity of Some Selected Competitive EMPs
LEACHING BEHAVIOUR OF SOIL AND IT’S CONSIDERATION IN DECIDING OPTIMAL EMPs
OPTIMAL ECOLOGICAL MANAGEMENT PRACTICES (EMPs)
INTRODUCTION
PURPOSE OF STUDY
A systematic approach to determine the degree of degradation of watersheds through a GIS-based river water quality monitoring system was also developed in this research work. The influence of sediment on stream water quality was also studied to set logical allowable limits of sediment yield for the optimization model.
OBJECTIVES
Experimental studies have been conducted to better understand the efficiency of some competing EMPs in controlling sediment yield. The influence of sediment on stream water quality was also investigated to establish logical allowable limits on sediment yield for the optimization model. v) Developing an optimization model for assigning the best EMP combination that limits sediment and water yield within the allowable limit, maximizes carbon sequestration, and minimizes total EMP costs.
METHOD OF INVESTIGATION
Scope of using optimization technique in land use planning for achieving sustainable solutions for a wide range of environmental problems has attracted the attention of researchers in recent years (Seppelt and Voinov, 2002; Gabriel et al. ,2006; Holzkamper and Seppelt, 2007, Riveira et al. 2008; Lin et al. 2009). With an objective to ensure sustainability of such OBP projects, the scope of including carbon sequestration benefit of vegetative OBPs in the optimization model was also analyses.
LITERATURE REVIEW
INTRODUCTION
HYDROLOGICAL MODELS AND THEIR APPLICATION TO LANDUSE PLANNING
- RAINFALL RUNOFF MODELS
- SEDIMENT YIELD MODELS
- HYDROLOGICAL MODELS FOR STUDYING IMPACT OF SEDIMENT AND OTHER NON POINT SOURCES POLLUTANT ON WATER
WEPP (Water Erosion Prediction Project) model is one of the most common models that predicts the amount of sediment yield. Hydrology, sediment and dynamic variable are the components of DANSAT. The dynamic variable component includes interactive soil, plant growth, and residue decomposition subcomponents that predict temporal changes in hydrology and discharge-related soil parameters, crop variables, and the decomposition of three. types of residues, respectively.
APPLICATION OF GIS AND REMOTE SENSING IN NATURAL RESOURCE MANAGEMENT AND LANDUSE
Melesse and Shih (2002) conducted a GIS and remote sensing-based study on the Kissimmee River sub-basin in south Florida to determine spatially distributed runoff curve numbers and runoff depth for the watershed for different land uses. In the study, GIS and remote sensing were used to provide quantitative measurements of drainage basin morphology for input into runoff models to estimate runoff response.
REVIEW ON LANDUSE BASED APPROACHES FOR CONTROLLING SEDIMENT AND OTHER NON POINT
According to Jain (2007), non-point source runoff is one of the important factors contributing to nutrient loading in the Ganga River in India. In addition to the width of the filter strip, grass type and flow rate were also important factors. 2008) used the SWAT model in the Upper Wakarusa watershed (950 km2) in northeastern Kansas to test the effectiveness of a vegetative filter strip (VFS) (0, 10, 15, and 20 m lengths) for sediment removal and faecal bacterial concentrations and ranking sub- watershed as determined.
PREVIOUS WORKS ON SEDIMENT LEACHING AND THEIR IMPACT ON WATER QUALITY
The mobility of nitrogen and phosphorus from the sediment was observed to increase with increasing salinity and temperature of the overlying water. The study found that greater concentrations of metals were released from smaller-sized sediments compared to larger ones, with the exception of copper.
USE OF OPTIMIZATION TECHNIQUE ON LANDUSE PLANNING
The GIS allocation model further specifies where the change in land use can occur to maintain the compatibility of land uses and the feasibility of physical conditions. Jiangqian (2007) proposed a basic framework for sensitivity analysis and continuous optimization of integrated land use and transportation model.
CONCLUSIONS
Therefore, it is important to examine the appropriateness and effectiveness of site-specific land use management practices in controlling sediment or other nonpoint pollution in order to achieve a cost-effective and sustainable site-specific management plan. Therefore, in order to have a quantitative idea of the effectiveness of different management practices of this kind, a field experimental study is needed for this region.
PRIORITIZATION OF DEGRADED WATERSHEDS
INTRODUCTION
Regular spatiotemporal monitoring of river water quality is also important for relatively pristine regions such as the northeastern region of India, where a large proportion of the rural and urban population depends on river water. This system was also used for river water quality assessment of the northeastern region of India, leading to the identification of seriously degraded watershed.
NEED AND SCOPE OF USING REMOTE SENSING AND GIS
In addition, this chapter proposes a systematic procedure to study the rate and pattern of urban expansion of degraded urban watersheds.
STRUCTURE OF THE RIVER WATER QUALITY INFORMATION SYSTEM (RWQIS)
APPLICATION OF RWQIS FOR NORTHEASTERN REGION OF INDIA
- STUDY AREA
- THE RIVER NETWORK DATABASE
- SOME ADDITIONAL DATABASES OF THE RIVER INFORMATION SYSTEM
- Watershed database
- LINKING OF DIFFERENT DATABASES IN THE GIS
- APPLICATION OF THE RWQIS IN PRIORITIZING DEGRADED WATERSHED OF NORTHEASTERN REGION OF INDIA,
River attribute tables were developed along with the river network map in GIS. The attribute table of this water quality database contains the following information:. i) Source of data (ii).
GEOINFORMATIC STUDY FOR ANALYZING SPATIOTEMPORAL GROWTH OF GUWAHATI CITY
- TIN MODEL, SLOPE MAP AND ASPECTS MAP OF GUWAHATI
- URBAN EXPANSION IN GUWAHATI CITY AND ITS IMPLICATION TO THE CATCHMENT AREAS
These maps have been superimposed and the hilly and flat parts of the city have been demarcated. In this study, the settlement areas in the hills and plains of the city in 1972 and 2000 were estimated; these are shown in Table 3.6.
CONCLUSIONS
INTRODUCTION
SCOPE OF THE EXPERIMENTAL STUDY
However, different cultivars with varied soil conservation potential are available within these groups (Shino et al., 2007; Millard and Santos, 2008; . Parajuli et al., 2008). The basic objectives of the development of the experimental watershed were (i) to investigate the hydrological response of residential development in terms of sediment and water yield, (ii) to create a facility to study the performance of some competing EMPs in terms of for soil conservation capability and ease of maintenance, and iii) to conduct experiments with some selected competing EMPs.
DESCRIPTION OF THE EXPERIMENTAL WATERSHED
- TOPOGRAPHIC MAPS OF THE EXPERIMENTAL WATERSHEDS
To understand the existing topographical features of the experimentally arranged Irregular Grid) the model was developed using the available contours of the area. To understand the existing topographic features of the experimentally arranged Irregular Grid) the model was developed using the available contours of the area.
METHODOLOGY
- DISCHARGE CHARACTERISTICS OF THE DISTURBED AND UNDISTURBED WATERSHEDS
- RECORD OF RAINFALL DATA
- STUDY OF SEDIMENT YIELD OF THE DISTURBED AND UNDISTURBED WATERSHED
- Collection and Analysis of Rainwater Samples
- Collection and Analysis of Runoff Samples
- Determination of Bicarbonate (HCO 3 -
- Determination of Hardness
Iw=Weight of the filter paper before filtration (mg) Fw=Weight of the filter paper after filtration (mg) V=Weight of sample taken (ml). The EDTA hardness of the water samples was determined by the titration method (APHA, WEF, AWWA, 1998).
ASSESSMENT OF SEDIMENT CONTROL CAPACITY OF SOME SELECTED COMPETITIVE EMP S
The study concluded that sediment removal efficiency increased from 50 to 98% as the width of the filter increased from 2.5 to 20 meters. Also, the longer strip retained more aggregates of the mm size class, which were dominant in the eroded sediment runoff from the plots.
RESULTS AND DISCUSSION
- DISCHARGE AND SEDIMENT YIELD CHARACTERISTICS OF DISTURBED AND UNDISTURBED WATERSHEDS
- COMPARISON OF RAINFALL AND RUNOFF WATER CHEMISTRY 1 Chemical Characteristics of Rainwater
- Chemical Characteristics of Runoff
The variation of pH in the runoff from the disturbed and the undisturbed watershed samples for 28 rainfall events is presented in Figure 22. The EC and TDS values in the runoff samples for 28 rainfall events were generally higher in the case of the disturbed watershed than the undisturbed watershed.
BDL BDL BD
- SEDIMENT YIELD CHARACTERISTICS OF SOME COMPETITIVE EMPs
The ionic contribution of the watershed area (land surface) to the runoff was assessed by calculating the percentage increase of the average values of the water quality parameters in the runoff of disturbed and undisturbed watersheds compared to that of rainwater (Table 4.8 and Figure 4.37). Higher sediment concentration appears to have a significant effect on the TDS and EC values of runoff.
CONCLUSIONS
Therefore, grass and Golden Glory can be used easily and with reasonable success as sediment control measures in hilly urban areas. Based on the research from the literature (Anbumozhi et al., 2005; Maillard et al.,2008; Parajuli et al.,2008), it is expected that the vegetative sediment controlling EMPs will also provide additional benefits in terms of nutrient loss from the soil and screening. of non-point source pollutants generated upstream.
LEACHING BEHAVIOUR OF SOIL AND IT’S CONSIDERATION IN DECIDING
OPTIMAL EMPs
INTRODUCTION
SCOPE OF THE LEACHING STUDY
METHODOLOGY
- COLLECTION OF SOIL SAMPLES FOR LEACHING STUDY
- DETERMINATION OF pH OF SOIL AND SEDIMENTS
- DETERMINATION OF ELECTRICAL CONDUCTIVITY (EC) OF SOIL AND SEDIMENTS
- SOIL DIGESTION METHOD
- SOIL LEACHING STUDY
- DETERMINATION OF pH AND ELECTRICAL CONDUCTIVITY (EC) OF LEACHATE SAMPLES
- ANALYSIS OF IONIC CONCENTRATION OF LEACHATE SAMPLES The digested soil samples and the leachate samples were analysed for Na, K, Ca and
U= Weight of the sample corrected to a dried sample at 1050C= 4 gm C= Trace element per gm of the dry sample, in µgm. The pH and EC of the leachate samples were tested immediately after filtration by the portable pH meter (Wagtech ) and EC meter (Wagtech).
RESULTS AND DISCUSSION
- LEACHING OF SOIL AND SEDIMENT
- LEACHING BEHAVIOUR OF SOIL OF EXPERIMENTAL WATERSHED OF IIT GUWAHATI
- LEACHING BEHAVIOUR OF SOILS OF GAMES VILLAGE WATERSHED
- LEACHING BEHAVIOUR OF BED SEDIMENTS
The leaching of Pb and Ni was more in the soil samples from the urban areas (sample code S12-S16) compared to the samples from the hilly watershed areas (Figure 5.5), except for one sample from the experimental watershed in the IIT Guwahati area. The leaching of Fe and Mn was much higher for the soil samples from the experimental watershed in the IIT Guwahati site (sample code S17-S28) than the other sites (sample code S1-S16) (Figure 5.6), except the Fe leachate for bottom sediment. of the Basistha River (sample code B2).
QUANTIFYING THE IMPACT OF SOIL LEACHING ON WATER QUALITY
- ESTIMATION OF NUTRIENTS AND METAL FLUX FROM A SMALL PART OF THE GAMES VILLAGE WATERSHED
- SETTING UP THE LIMIT FOR MINIMUM SEDIMENT YIELD REQUIRED BY WATER BODIES
- ESTIMATION OF THE MINIMUM REQUIRED SEDIMENT YIELD FROM THE GAMES VILLAGE WATERSHED
By understanding the behavior of soil leaching from the Games village catchment, the amount of nutrient and metal losses from a small part of the Games village catchment has been estimated. ESTIMATION OF THE MINIMUM SEDIMENT RANGE REQUIRED FROM THE GAME VILLAGE AREA FROM THE GAME VILLAGE AREA.
CONCLUSIONS
The results of the determination of the main cations and trace metals in soil and their leaching amount to water are used to estimate the annual loss of nutrients and trace metals that occurs due to soil erosion from the area. Incorporating the role of soil and sediment in absorbing and adsorbing pollutants from water will increase understanding for determining minimum sediment yield requirements from a watershed.
OPTIMAL ECOLOGICAL MANAGEMENT PRACTICES (EMPs)
INTRODUCTION
SCOPE OF APPLYING EMPs AND OPTIMIZING EMP COMBINATION
In addition, some studies have also reported the effectiveness of detention pond in controlling non-point pollution such as sediment and nutrients. While many investigators have reported the successful application of land management practices for the control of nonpoint source pollution, study of application of such practices in the urban sector is limited.
CONCEPT OF OPTIMAL EMPS FOR CONTROLLING SEDIMENT AND WATER YIELD FROM HILLY URBAN
Depending on the status of degradation of the waterway, different types of vegetation can be proposed. vi) Rainwater harvesting system: Rainwater harvesting is a technique of collecting and storing rainwater in surface (storage tanks) or underground aquifer before it is lost as surface runoff. Case B: This approach can be applied to a relatively large watershed, where there may be several plots in sequence from upstream to downstream under different ownership.
MODEL FORMULATION
- MODEL FORMULATION FOR A WATERSHED WITH SINGLE OWNERSHIP: OPTEMP-LS MODEL
- MODEL FORMULATION FOR LARGE WATERSHED WITH DIFFERENT OWNERSHIP
Ci = coverage factor for the ith EMP on the plot (dimensionless) Aj = area of the jth coverage on the plot (m2). Ci k = coverage factor for the i-th EMP on the k-th plot (dimensionless) Aj k = area of j-th coverage on the k-th plot (m2).
CASE STUDY
- APPLICATION OF THE OPTEMP-LS MODEL AND SENSITIVITY ANALYSIS OF THE MODEL PARAMETERS
The results of OPTEMP-LM considering four plots in the watershed are presented in Table 6.8. In Figure 6.17, the cost of PMMs for the four watershed parcels as obtained by OPTEMP-LM and OPTEMP-LDM is shown.
SUSTAINABILITY ANALYSIS
- SUSTAINABILITY THROUGH MAXIMIZATION OF CARBON SEQUESTRATION OF EMPs
- PROBLEM FORMULATION
- MODEL APPLICATION
A specific study was conducted by Lasco et al. 2002) in the Leyte Geothermal Reserve of the Philippines to determine the total carbon sequestration of various vegetation based on biomass change. CSi = Amount of carbon sequestration (tonnes/yr) from the i-th EMP in the plot with an area of ai.
