An integrated study of geospatial information technologies for surface runoff estimation in an agricultural watershed,India

Runoff is one of the important hydrologic variables used in most of the water resources applications. The Soil Conservation Service-Curve Number (SCS-CN) method is adopted for the estimation of surface runoff in the Mehadrigedda watershed area, Visakhapatnam district, India using multispectral remote sensing data, curve number approach and normal rainfall data. The main source of water in the Mehadrigedda watershed area is by rain, most of it drains off and only a little percolates into ground. The weighted curve number is determined based on antecedent moisture condition (AMC)-II with an integration of hydrologic soil groups (HSGs) and land use/land cover LULC categories. An integrated approach is applied to delineate the land use/land cover information as adopted from NRSA classification. The recording of daily rainfall data during the years 1997–2006 is collected from Indian Meteorological Department (IMD) rainguage center at Kottavalasa. It is observed that the annual rainfall-runoff relationship during 1997–2006, which is indicating that the overall increase in runoff with the rainfall of the watershed area. Integration of remote sensing (RS) and geographical infomation system (GIS) techniques provide reliable, accurate and up-to-date information on land and water resources.     

Hydrological modelling of a small watershed using satellite data and gis technique

A distributed parameter model Soil and Water Assessment Tool (SWAT) has been tested on daily and monthly basis for estimating surface runoff and sediment yield from a small watershed “Chhokeranala” in eastern India using satellite data and Geographical Information System (GIS). Several maps like watershed and sub-watershed boundaries, drainage network, landuse/cover and soil texture have been generated. The SWAT model has been verified for the initial phase of monsoon season in the year 2002 using daily rainfall and air temperature. Performance of the model has been also evaluated to simulate the surface runoff and sediment yield on sub-watershed basis for two months (July-August 2002). The results show a good agreement between observed and simulated runoff and sediment yield during the study period. Capability of the model for generating rainfall has been evaluated for 10 years (1992 - 2001) period. The model simulated daily rainfall shows close agreement with the observed rainfall. The present results show that the SWAT model can be used for satisfactory simulation of daily and monthly rainfall, runoff and sediment yield.     

Selection of suitable sites for water harvesting structures in Soankhad watershed,Punjab using remote sensing and geographical information system (RS&;GIS) approach— A case study

A case study has been conducted to identify suitable sites for water harvesting structures in Soankhad watershed, Punjab using information technologies such as Remote Sensing and Geographical Information System (RS-GIS). The IRS-1C, P6 satellite imagery of the Soankhad watershed was used. The various Thematic maps such as land use map, hydrological soil group map, slope map and DEM map were prepared for selecting suitable site for construction of water harvesting structures. The suitable sites were not found for nala bunding and farm ponds due to steep slope, less soil thickness and high runoff velocity. Fourteen check dams and six percolation tanks were proposed for the construction as per Integrated Mission for Sustainable Development (IMSD) guidelines. The water balance study of the Soankhad watershed was also computed with monthly mean temperature and rainfall data using TM model. The average runoff for the wet season (July–September) 1996 was computed to be about 1543.82 mm and the total runoff volume from the Soankhad watershed was estimated to be about 143.52 Mm³.     

Sustainable Utilisation of Water Resource in Watershed Perspective - A Case Study in Alaunja Watershed, Hazaribagh, Bihar

Alaunja watershed, located on ‘Chotanagpur’ plateau of Bihar, is mainly under single cropping. The area receives more than 1000 mm of rainfall but it has not been utilised properly to increase the agricultural output. The remote sensing, geophysical, DBTM (Digital Basement Terrain Model) and GIS (Geographic information System) techniques were used for providing scientific database for sustainable utilisation of water resources in watershed perspective. The landuse, soil and surface water body maps have been prepared using remotely sensed data. DBTM has been generated based on depth of basement information derived from geophysical data to provide information regarding aquifer geometry, fracture zones and sub-surface basins. Analysis indicated that surface and groundwater resources have potential to irrigate 53 per cent of geographical area of the watershed. But at present, this available potential has been utilised only to irrigate 7.03 per cent area of the watershed. Feasibility for large scale development of groundwater through dugwell is possible only in 2 per cent area of the watershed. The available groundwater potential to irrigate 28 per cent area of watershed can not be utilised through dugwells. The surface water potential is also poorly utilised. The present study also helped in prioritising the water resource development activities.     

Use of high-resolution satellite data,GIS and NRCS-CN technique for the estimation of rainfall-induced run-off in small catchment of Jharkhand India

The present study demonstrates the use of NRCS-CN technique for rainfall-induced run-off estimation using high-resolution satellite data for small watershed of Palamu district, Jharkhand. The CN model was applied to the daily rainfall data of 15 years (1986–2000) along with use of large-scale thematic maps (1:10,000) pertaining to land use/land cover using IRS-P6 LISS-IV satellite data. The LU/LC map was spatially intersected with the hydrological soil group map to calculate the watershed area under different hydrological similar units for assigning CN values to compute discharge. The study showed that Daltonganj watershed exhibits an average run-off volume of 7,881,019 m³ from an average cumulative monsoon rainfall of 821 mm and the average actual direct run-off generated during the southwest monsoon season was 203 mm. The strong correlation between rainfall and run-off as well as between observed run-off and estimated run-off indicated high accuracy of run-off estimation by NRCS-CN technique.     

Runoff modelling of a small watershed using satellite data and GIS

This study was conducted for the Nagwan watershed of the Damodar Valley Corporation (DVC), Hazaribagh, Bihar, India. Geographic Information System (GIS) was used to extract the hydrological parameters of the watershed from the remote sensing and field data. The Digital Elevation Model (DEM) was prepared using contour map (Survey of India, 1:50000 scale) of the watershed. The EASI/PACE GIS software was used to extract the topographic features and to delineate watershed and overland flow-paths from the DEM. Land use classification were generated from data of Indian Remote Sensing Satellite (IRS-1B—LISS—II) to compute runoff Curve Number (CN). Data extracted from contour map, soil map and satellite imagery, viz. drainage basin area, basin shape, average slope of the watershed, main stream channel slope, land use, hydrological soil groups and CN were used for developing an empirical model for surface runoff prediction. It was found that the model can predict runoff reasonably well and is well suited for the Nagwan watershed. Design of conservation structures can be done and their effects on direct runoff can be evaluated using the model. In broader sense it could be concluded that model can be applied for estimating runoff and evaluating its effect on structures of the Nagwan watershed.     

Rainfall-runoff and soil erosion modeling using Remote Sensing and GIS technique — a case study of tons watershed

In the present study, the rainfall-runoff relationship is determined using USDA Soil Conservation Service (SCS) method. The coefficient of determination (R2) is 0.99, which indicates a high correlation between rainfall and runoff. The runoff potential map was prepared by assigning individual class weight and scores input map. Annual spatial soil loss estimation was computed using Morgan, Morgan and Finney mathematical model in conjunction with remote sensing and GIS techniques. Higher soil erosion was found to occur in the northern part of the Tons watershed. The soil texture in the affected area is coarse loamy to loamy skeletal and soil detachment is higher. Moreover the land use has open forests, which does not reduce the impact of rainfall. The average soil loss for all the four sub-watersheds was calculated, and it was found that the maximum average soil loss of 24.1 t/ha occurred in the sub-watershed 1.     

Runoff Estimation and Morphometric Analysis for Hesaraghatta Watershed Using IRS–1D LISS III FCC Satellite Data

The study area, Hesaraghatta watershed is located between 77° 20′ to 77° 42′ E longitude and 13° 10′ to 13° 24′ N latitude with an area of 600.01 km². Thematic layers such as Land Use/Land Cover, drainage, soil and hydrological soil group were generated from IRS–1D LISS III satellite data (FCC). An attempt was made to estimate runoff using Soil Conservation Service (SCS) curve number model and it was estimated to be 1960, 2066, 1870 and 1810 mm for sub-watersheds 1, 2, 3 and 4 respectively. Quantitative morphometric analysis was carried out for the entire watershed and the four sub-watersheds independently by estimating their (a) linear aspects like stream order, stream length, stream length ratio, bifurcation ratio, length of overland flow, drainage pattern (b) aerial aspects like shape factor, circulatory ratio, elongation ratio and drainage density and (c) relief aspects like basin relief, relief ratio, relative relief and ruggedness number. Drainage density was estimated to be 1.23 km/km² designating the study area as a very coarse textured watershed.     

Catchment infiltration II: Contributing areas

This study considers two issues of interest to the hydrologic and geographical information systems community. One deals with identifying the spatial distribution of infiltration and runoff contributing areas. The other addresses process modelling within a GIS framework. The study operates on the premise that partitioning of precipitation into runoff or infiltration depends on rainfall intensity and on soil properties. The problem is that neither local rainfall intensity, nor soil properties such as infiltration capacity and macroporosity are known well enough for all points of a catchment and need to be estimated. We infer local intensity from the interpolated distribution of cumulated rain depths over the catchment and record duration at the official met site. Measured values of sorptivity and hydraulic conductivity define infiltration. Negative head infiltration describes macroporosity. To scale-up measured point values to larger areas and to model infiltration and macropore continuity at a catchment scale we use geostatistical kriging and conditional simulation together with standard GIS techniques of overlay manipulation. Results delineate areas contributing to runoff and infiltration and relate them to macroporosity. By intersecting overlays of precipitation with those of infiltration we create alternate GIS masks targeting specific portions of the watershed as either runoff or infiltration contributing zones. Choice of cell size and time interval define the scales of averaging for the application. Kriged surfaces illustrate the distribution of catchment infiltration, while conditional simulation provides a mechanism to define model uncertainty.     

Predicting the Impact of Coastal Development on Water Quality Using Remote Sensing and GIS‐assisted Hydrologic Modeling Techniques

Abstract

A decline in water quality in the Okatie River, a coastal estuary located in Beaufort County, SC, has resulted in the closure of several shellfish beds. Continuing urban development within the watershed has altered land cover conditions and may be contributing to the recent decline in water quality. Remote sensing and geographic information system (GIS) technology, coupled with a water quality model were used to spatially model stormwater runoff to understand the relationship between recent changes in land cover and watershed runoff characteristics. High spatial resolution imagery acquired in 1994 and 1996 spatially documented pre‐ and post‐development land cover conditions within the watershed. The water quality model Agricultural Nonpoint Source Pollution (AGNPS) evaluated land characteristics such as soil type, topography, and land cover to simulate surface water flow and sediment transport over past and current land cover conditions. Results of the model were used to locate net increases of fresh water discharge and to suggest best management practices (BMP).     

GIS-based evaluation of micro-watersheds to ascertain site suitability for water conservation structures

The planning of conservation measures to conserve water and soil resources taking hydrological planning unit as micro-watershed is considered to be effective. The automated watershed delineation technique using the spline interpolated filled digital elevation model (DEM) is effective in converging slopes of the area in which the stream patterns match with the manually digitized stream patterns of the topographical map. The various vector spatial layers like the slope/aspect, land-use/land-cover, runoff potential, soil erosion potential and the associated attribute information governing the criteria for different conservation structures can act as input layers in integrated spatial analysis module in GIS environment to evolve derived layers indicating the locations of conservation sites meeting the requisite criteria. The reliability of suitable conservation sites suggested out of integrated spatial GIS analysis could be ascertained using the multi criteria analysis incorporating the various factors controlling soil erosion process in the micro-watershed groups. The details of the above work are discussed in the paper.     

Effects of watershed discretization on estimation of hydrologic parameters

This study evaluates how watershed discretization affects estimation of hydrologic parameters using GIS data. Two aggregation methods were evaluated using three GIS data sets for a large watershed in Kansas, which is discretized into five different levels. The two aggregation methods are weighted-average and dominant-value. The three GIS data sets, soils, land use, and temperature, constitute three commonly used hydrologic parameters with distinct spatial patterns. The study evaluated the aggregation effects measured in terms of statistical distribution, spatial distribution, information level, and spatial dependence of the aggregated data. Results indicate that: (1) statistically, the mean and modal values of the source data are well preserved through aggregation but with a reduced standard deviation; (2) changes in spatial patterns are less predictable than those of the statistical distribution, and the changes depend on the geometric similarity and spatial overlap between the source and target polygons; (3) the information level in general decreases with aggregation for the dominant method, and it increases for the average method although the original values are altered; and (4) spatial dependence generally increases with aggregation.     

Watershed Delineation in Flat Terrain of Thar Desert Region in North West India – A Semi Automated Approach Using DEM

Thar desert spreads in western part of Rajasthan, northern part of Gujarat, and some parts of Punjab and Haryana. The terrain is dominated by slightly sloping plains, broken by some dunes and low barren hills. The area is characterized by low average annual rainfall which is erratic in distribution and intensity. Drought will remain a major hindrance for agricultural production in Thar desert. Due to water stress condition, many watershed based development activities has been adopted by government and non-government organizations for the growth and sustainable development of this region. The need of this hour is preparation of a national level watershed atlas of 1:50,000 scale because majority of thematic maps are being produced presently on same or 1:10,000 scale. The manual delineation of watershed boundary in flat terrain based on topographic map will be time consuming and less accurate in the absence of prominent contour lines. Automated approach for watershed delineation using Digital Elevation Model (DEM) along a suitable algorithm has the advantage because the output is not only less time consuming but also independent from human decisions. Hence, a case study has been carried out in Churu sub-basin part of Indus basin which is located in Thar desert region. Depression less DEM with different spatial resolutions was used as input in hydrology tool of ArcGIS spatial analyst function for characterization of watersheds. The Churu sub-basin has been divided into various numbers of watersheds with an average size of 600 km². These watershed boundaries have been validated with respect to high resolution satellite imageries (IRS P6 LISS IV), Survey of India toposheets, ancillary data and limited field checks.     

Variability analysis of groundwater levels — AGIS-based case study

The present study has analyzed the variability in depth to water level below ground level (bgl) vis-à-vis groundwater development and rainfall from 1987 to 2007 in agriculture dominated Kaithal district of Haryana state in India. Spatial distribution of groundwater depth was mapped and classified into different zones using ILWIS 3.6 GIS tools. Change detection maps were prepared for 1987–1997 and 1997–2007. Groundwater depletion rates during successive decades were compared and critical areas with substantial fall in groundwater levels were identified. Further, block wise trends of change in groundwater levels were also analyzed. The water table in fresh belt areas of the district (Gulha, Pundri and Kaithal blocks) was observed to decline by a magnitude ranging from 10 m to 23 m. In Kalayat and Rajaund blocks, the levels were found fluctuating in a relatively narrow range of 4–9 m. During 1997–2007, the depletion has been faster compared to the preceding decade. Excessive groundwater depletion in major part of the district may be attributed to indiscriminate abstraction for irrigation and decrease in rainfall experienced since 1998. Changes in cropping pattern and irrigation methods are needed in the study area for sustainable management of the resource.     

徐州贾汪矿塌陷积水区变化特征的研究

本文采用遥感(RS)获取信息和地理信息系统(GIS)建库分析相结合的方法,对徐州贾汪矿区1987-2007年煤炭开采过程中形成的塌陷积水区的数量变化、形态特征变化以及破碎度变化特征及其成因进行了研究,结果表明1987-2007年间,由于开采活动的不断进行,常年积水塌陷区的面积逐步增加;1987-1997年10年间,季节性塌陷积水区与常年塌陷积水区具有相似的变化特征;1997-2007年10年间,由于部分矿井停止开采及土地复垦的推行,季节性塌陷积水区的数量锐减,斑块形状变得规则且分布趋于分散。     

长江上游重点水土流失区遥感动态监测及泥沙输移分析

以嘉陵江流域重点产沙区为试点,选择1992和1996年两个时段,通过遥感、GIS以及数学模型相结合的方法对水土流失现状和水土保持效益进行调查分析,建立水土流失变化动态监测信息系统,并从流域的土壤侵蚀推测和分析流域河流泥沙的输移变化。     

基于流域GIS空间建模的雨洪模拟方法

基于多层次GIS空间分析模型技术,系统地建立了从流域雨洪过程相关影响因子栅格化处理到产汇流过程模型的集成化模拟方法,首次实现了对流域内任意栅格单元内河道断面的径流过程线的可视化测算。同时还对于模型中单元水流长度与河道单元流速率定方法进行了优化改进。实例分析结果表明:模型结构更为严谨、参数设置更为科学,改进的技术方法对于福建汀江十年一遇洪水场次的模拟结果精度有明显提高,能够满足相关海绵城市规划应用需求。     

Albedo-rainfall Feedback Over Indian Monsoon Region Using Long Term Observations Between 1981 to 2000

Albedo determines radiation balance of land (soil-canopy complex) surface and influence boundary layer structure of the atmosphere. Accurate surface albedo determination is important for weather forecasting, climate projection and ecosystem modelling. Albedo-rainfall feedback relationship has not been studied so far using observations on spatial scale over Indian monsoon region due to lack of consistent, systematic and simultaneous long-term measurements of both. The present study used dekadal (ten-day) composite of satellite (e.g. NOAA) based Pathfinder AVHRR Land (PAL) datasets between 1981 and 2000 over India (68–100°E, 5–40°N) at 8 km spatial resolution. Land surface albedo was computed using linear transformation of red and near infrared (NIR) surface reflectances. The cloud effects were removed using a smoothening filter with harmonic analysis applied to time series data in each year. The monthly, annual and long term means were computed from dekadal reconstructed albedo. The mean per year and coefficient of variation (CV) of surface albedo over seventeen years, averaged over Indian land region, were found to show a significantly decreasing (0.15 to 0.14 and 60 to 40%, respectively) trend between 1981 and 2000. Among all the land use patterns, the inter-annual variation of albedo of Himalayan snow cover showed a significant and the steepest reducing trend (0.42 – 0.35) followed by open shurbland, grassland and cropland. No significant change was noticed over different forest types.. This could be due to increase in snow melting period and snow melt area. A strong inverse exponential relation (correlation coefficient r = 0.95, n = 100) was found between annual rainfall and annual albedo over seven rainfall zones. The decreasing trend in snow-albedo of accumulation period (September to March) follows the declining trend in measured south-west monsoon rainfall between 1988 (980 mm) to 1998 (880 mm) over India. This finding perhaps suggests the possible reversal of reported coupling of increased snowfall followed by lower monsoon rainfall.