Water Spread Area Research Articles

Effects of Stocking Density on Growth Performance, Survival and Production of Catla catla and Labeo rohita During Nursery Rearing in Cages

A nursery rearing experiment of fry to fingerling was conducted in cages in Dimbhe reservoir of Pune District of western India, located at 19°06′ N, 73°44′ E to evaluate optimum stocking density for better growth performance and production of Indian Major Carps, Catla (Catla catla) and Rohu (Labeo rohita) using formulated feed with 36% protein. The culture experiment was carried out in triplicate for the period of 115 days. Catla and Rohu fry of 36 ± 1.75 mm were stocked in four different stocking densities viz T1 (900 no), T2 (1800 no), T3 (2700 no) and T4 (3600 no) in 18 m3 water spread area of 3 × 3 × 3 m sized cages. The composition of catla and rohu was 55 and 45%, 47 and 53%, 40 and 60% and 43 and 57% in T1; T2; T3 and T4 respectively. Results of the study found significantly (p 100 mm size in 115 days in cages. These findings aid in providing guideline for stocking density of fry rearing in nursery cages to improve sustainability of freshwater carp farming in cages.

Assessment of sedimentation in Pong and Bhakra reservoirs in Himachal Pradesh, India, using geospatial technique

All water storage structures constructed on natural rivers are subjected to reservoir sedimentation. The reservoir sedimentation is filling of the reservoir behind a dam with sediment carried into the reservoir by streams. The sediment particles which originate from erosion processes in the catchment are propagated along with the river flow. When the flow of a river is stored in a reservoir, the sediment settled down in the reservoir and reduces its capacity. Decrease in the storage capacity of a reservoir beyond a limit hampers the purpose for which it was constructed. Therefore, assessment of sediment deposition becomes very important for the management and operation of such reservoirs. Some conventional methods, such as hydrographic survey and inflow-outflow approaches, are being used to estimate the sediment deposition in a reservoir, but these methods are tedious, time-consuming and costly. Consequently, in this study, a remote sensing data based digital image processing technique was used to assess the sedimentation in Pong and Bhakra reservoirs, located in foothill of Western Himalayas, India. Seven dates of IRS-(P6) LISS-III satellite data from maximum to minimum reservoir level were used to assess temporal and spatial patterns of reservoirs. The water spread areas of the reservoirs were assessed by using a band rationing technique i.e. Normalized Difference Water Index (NDWI). Furthermore, the revised capacities of the reservoirs between minimum and maximum levels were computed using the trapezoidal formula. From the analysis, it has been observed that the live storage capacity of Pong Reservoir, due to sedimentation, was estimated as 632.84Mm3 in last 35 years (1974–2009), whereas it was determined as 802.34Mm3 for Bhakra reservoir in the span of 46 years (1963–2009). Further, the sedimentation rate in the Pong reservoir was calculated as 18.08Mm3/year, while for the Bhakra reservoir it was 17.46Mm3/year. These sedimentation rates are comparable with the hydrographic survey analysis.

Updated Inventory of Glacial Lakes in Teesta Basin Using Remote Sensing Data for Use in GLOF Risk Assessment

Detailed inventory of glacial lakes in a Glacial Lake Outburst Flood (GLOF) prone area is vital for disaster mitigation. Availability of cheaper high resolution satellite data from Indian remote sensing satellites enables us to create up-to-date inventory for use in prioritisation of glacial lakes for GLOF risk assessment. Earlier inventories show presence of more glacial lakes in Brahmaputra basin in Indian Himalaya. Teesta River is one of the tributary of Brahmaputra and previous studies have shown that the inventory of glacial lakes in Teesta basin varies from 143 to 320. In the present study, the inventory carried out using satellite data of years 2000, 2007 and 2014 show presence of 301 (25.789 km2), 302 (26.081 km2) and 644 (29.706 km2) glacial lakes in Teesta basin respectively. The steep increase in number of lakes in the latest inventory is primarily due to the finer spatial resolution of satellite data used. Analysis of water spread area of glacial lakes at different altitudes shows that most of the lakes in the higher altitudes are small in size. It is observed that more than 66% of lakes are in the altitude beyond 4500 m and of size less than 50,000 sqm (5 ha). Out of 301 glacial lakes inventoried during 2000, water spread area of 6 lakes have decreased in 2014 and 31 lakes have shown increase in area. Out of these 31 lakes, 17 lakes are classified as end moraine dammed lakes and among them, 14 are located in Upper Teesta sub-basin and in higher altitudes (beyond 5000 m). The prioritisation of these lakes for GLOF risk needs to be carried out with detailed field investigation.

Nutrient modeling for a semi-intensive IMC pond: an MS-Excel approach.

Semi-intensive Indian Major Carp (IMC) culture was practised in polythene lined dugout ponds at the Aquacultural Farm of Indian Institute of Technology, Kharagpur, West Bengal for 3 consecutive years at three different stocking densities (S.D), viz., 20,000, 35,000 and 50,000 numbers of fingerlings per hectare of water spread area. Fingerlings of Catla, Rohu and Mrigal were raised at a stocking ratio of 4:3:3. Total ammonia nitrogen (TAN) value along with other fishpond water quality parameters was monitored at 1 day intervals to ensure a good water ecosystem for a better fish growth. Water exchange was carried out before the TAN reached the critical limit. Field data on TAN obtained from the cultured fishponds stocked with three different stocking densities were used to study the dynamics of TAN. A developed model used to study the nutrient dynamics in shrimp pond was used to validate the observed data in the IMC pond ecosystem. Two years of observed TAN data were used to calibrate the spreadsheet model and the same model was validated using the third year observed data. The manual calibration based on the trial and error process of parameters adjustments was used and several simulations were performed by changing the model parameters. After adjustment of each parameter, the simulated and measured values of the water quality parameters were compared to judge the improvement in the model prediction. Forward finite difference discretization method was used in a MS-Excel spreadsheet to calibrate and validate the model for obtaining the TAN levels during the culture period. Observed data from the cultured fishponds of three different S.D were used to standardize 13 model parameters. The efficiency of the developed spreadsheet model was found to be more than 90% for the TAN estimation in the IMC cultured fishponds.

Environmental degradation of a tropical estuary due to human interferences—a case study from southern Kerala, SW India

The estuaries in the densely populated tropical coasts like Kerala (SW India) have been subjected to severe degradation due to various kinds of human interventions. Here, we report the case of environmental degradation of Paravur estuary in southern Kerala, southwest India, as an example. Large-scale extraction of alluvial deposits (sand and brick clay), improper engineering constructions, and other developmental initiatives are some of the interventions that have imposed immense stress on the system. Indiscriminate extraction of sand and clay has disrupted a major part of the drainage network at its upstream end, leaving the alluvial belt almost completely water logged. Land use changes show a significant increase in the water spread area of the estuary (6.31 to 7.85 km2), over the last century, with a concomitant decrease in alluvial/floodplain deposits (4.95 to 2.12 km2). The engineering interventions like the Flood Water Outlet System (FWOS) and its poor maintenance imposed marked changes in the sediment balance of the coastal zone, which ultimately led to the development of a flood tide island (FTI) (0.10 km2) in the estuary. The growth of the island, if not arrested by appropriate corrective measures, would lead to filling up of a greater part of the estuary at its southwestern end in the near future. The corresponding dearth of sand in the littoral zones on the other hand could exacerbate the hungry water effect of coastal waters. This, in turn, aggravates coastal erosion in the cliffed coast in the southern side of the FWOS. Considering the extent of human interventions in the estuary, an attempt has been made in this paper to address in detail about the different causes and effects of degradation of the system. Based on the study, a set of recommendations are also drawn to revive the Paravur estuary in particular and tropical estuaries of similar kinds in general.

Estimation of Water-Spread Area of Singoor Reservoir, Southern India by Super Resolution Mapping of Multispectral Satellite Images

Estimation of reservoir water-spread area is often carried out by field surveys which are cumbersome, time consuming, expensive and involves more man power. Hence, such surveys cannot be carried out periodically. To overcome this issue, satellite images are used, wherein the reservoir water-spread is estimated by conventional per-pixel classification such as the maximum likelihood and minimum distance to mean approaches that often results in inaccurate estimate of water-spread area due to the presence of mixed pixels. High cost and non-availability of high resolution images demands the use of an alternative approach that can give accurate information about the reservoir water-spread area. In this work, IRS, LISS III images of moderate (24 m) resolution were used for accurate estimation of the water-spread area of Singoor reservoir, southern India. The reservoir water-spread areas were extracted using per-pixel classification, sub-pixel classification and super resolution mapping approaches. These results were validated with the water-spread areas obtained from field data of the same dates. The error produced by the per-pixel approach was 6.66%, while it was 4.37% for the sub-pixel approach and a meagre 1.71% for the super-resolution approach. Fairly less error produced by the super resolution mapping technique implies that it is an efficient approach for accurate quantification of reservoir water-spread area. The estimated water-spread can be used in a simple volume estimation formula to estimate the capacity of the reservoir.

Length-weight relationship of six indigenous fish species from Deepor beel, a Ramsar site in Assam, India

Length–weight relationships for six small indigenous fish species, namely: Trichogaster chuna (Hamilton, 1822), Trichogaster lalius (Hamilton, 1822), Trichogaster fasciata Bloch & Schneider, 1801, Chanda nama Hamilton, 1822, Parambassis lala (Hamilton, 1822), and Macrognathus aral (Bloch & Schneider, 1801) were studied for the first time from Deepor beel, a Ramsar site (589 ha water spread area) located in Assam, India. A total of 617 fish specimens were collected for the present study on a monthly basis from February to August in 2016 from landing centres adjoining the beel. In the present study, b value ranges from 2.778 to 3.215, which is within the normal range. The LWRs for these six fish species from Deepor beel had not yet been reported for FishBase.

Status of Sarus Crane (<I>Grus antigone</I>, Linn.) in Madhya Pradesh, India

The Sarus Crane (Grus Antigone, Linn.) is considered Vulnerable at the international level by IUCN but has been included in Schedule IV of Indian Wildlife Protection Act, 1972 amended till date. One of the largest and the most dominant species in India, which has been declared as the State Bird of Madhya Pradesh, logically deserve serious studies on its current status. In the present study, special focus was given to the preferred habitats i.e., large agricultural farmland and wetland areas, which are distributed in 26 districts of the state. In addition 07 more districts were also surveyed in two years period. During the survey, direct sightings along with geo-references have been recordedand photographed.. Additional information were collected by interacting with the local community and meticulously recorded. A total of 347 individual birds were recorded through direct sighting during the project period and if one adds the reports from the local community, the total number of birds now stands at 491 birds. But one has to remember the limitation of this methodology, which does not exclude the possibility of repeat sighting of the same bird at a different location. As such, to exclude such possibilities, same day census operation at all the selected locations, by deploying large number of ground staff, could be undertaken in future.Besides incorporating the data on the locations and sightings, suitable recommendations have been made towards its conservation action, especially focusing on the need for extensive Public Awareness Programme through appropriate visual display. It has also been pointed out that land use changes, both in case of large agricultural land and water-spread areas should be appropriately controlled as a part of State Policy for conserving the State Bird of Madhya Pradesh.

Pulicat Lake: A Fragile Ecosystem Under Threat

Abstract The Pulicat Lake is the second largest brackish water lake after Chilika Lake in India. The average area of the water spread is 461 sq km. During the monsoon Pulicat Lake receives freshwater through three major rivers, namely, the Swarnamukhi, the Kalangi and the Arani. The Pulicat lagoon system, which is a storehouse of rich biological resources, is under great threat because of the anthropogenic influences. The Pulicat Lake ecosystem is degraded by siltation, bar mouth dynamics, shell mining and processing and population pressure due to the resettlement of villagers from Sriharikota Island. It has been determined that the extent of the lake, including its water spread area, is decreasing. Therefore, it is essential to assess the land use / land cover changes taking place in and around Pulicat Lake using remote sensing and GIS. Studies on its sediment characteristics are also vital. The grain size content reveals that most of the sediments contain clay and silt in enormous amounts. This lake has been the prime source of a livelihood through fishing for a large section of the population living in the surrounding villages. It is the most important refuge for water birds in south India. The fishing community who lives in and around Pulicat Lake follows the Padu system for fishing in the lake. In this study, apart from studies on configuration changes and sediment analysis, a study of the flora and fauna of the lake and the socio-economic conditions of the local community were also carried out. Finally, mitigation measures for the sustainable protection of the lake’s ecosystem were identified.

Temporal Geomorphological Changes in Nanak Sagar Reservoir (INDIA) Using Satellite Data

An attempt was made to assess the sedimentation in Nanak Sagar reservoir using multi-dated Remote Sensing (RS) images. IRS LISS III and Landsat-8 (OLI) remote sensing data were taken in the year 2007 and 2015, respectively. The original capacity curve (1962) was optimized for the study of the capacity loss to various water levels. Results showed that the morphology of the reservoir has been changed significantly due to sedimentation from 1962 to 2015. The reservoir has lost a total of 2934.64 hectares (ha) by dint of sedimentation which is accounted for 59.89 % of the total water spread area during last 53 years and average deposition was computed as 1.13% per year. From the year1962 to 2007 maximum siltation deposited in Full Storage Level (FRL) of the reservoir and from 2007 to 2015 in Dead Storage Level (DRL)in the period 2007 to 2015. It can be concluded that multi-dated remote sensing images can be used as a valuable tool for the study of temporal as well as spatial changes in any large water body.

Reservoir capacity estimation using SARAL/AltiKa altimetry data coupled with Resourcesat P6-AWiFS and RISAT 1 microwave data

Reservoir water levels extracted from SARAL/AltiKa GDR data for the period 2013–2014 and water spread areas delineated from Resourcesat P6-AWiFS sensor and RISAT 1 microwave data corresponding to SARAL/AltiKa cycles were used for assessment of reservoir capacity in the Mayurakshi reservoir, Jharkhand state, India. It was found that the reservoir capacity based on the SARAL is around 474.62 Mm3 in comparison to in situ based estimate i.e. around 486.6 Mm3, indicating variation of <3%. Further, comparison of these estimates computed using SARAL and in situ with original reservoir capacity (547.59 Mm3) indicated loss of reservoir capacity is around 13.33 and 11.14%, respectively, within a span of 59 years. The hydrographic survey in the year 1999–2000 also proved that the storage capacity has reduced from 547.6 Mm3 in 1955 to 474.8 Mm3 indicating loss of nearly 13.3 % of total live capacity over period of 45 years.

English

Rajasthan state has a water spread area of 3 lac ha ctares including large reservoirs, medium reservoirs, tanks in villages, canals, seasonal wat er, rivers and water logged areas. Water supports a variety of plants and animals. The study of Phytoplankton are the subject of great interest because of their role as primary producers in an aquatic ecosystem. Phytoplankton ar e assemblages of heterogeneous microscopic algae forms whose movement is more or less dependen t upon water currents. The present study was undertaken to explore the diversity and ecology of phytoplankton in Sadul branch of Sirhind Feeder in Hanumangarh (29o5’ to 30o6’ north latitude and 7 4 o3’ to 75 o3’ east longitudes). The present observations were made for a period of six months. Physical-Chemical limnology revealed that canal was shallow with turbid, alkaline, hard salin e and well oxygenated water. The flora was collected with plankton net. The stud y revealed the occurrence of 27 species of phytoplankton, among these 12 species of Bacillario phyceae, 9 species of chlorophyceae, 3 species of cyanophyceae and 1-1 species of zygnemataceae, m yxophyceae and chaetophoraceae were recorded. The flora was identified following Edmans on 6 , Round 11 , Chapman & Chapman 5 and Needham & Needham 10 .

Assessment of reservoir sedimentation using remote sensing and recommendations for desilting Patratu Reservoir, India

ABSTRACTThis study describes the assessment of reservoir sedimentation of the Patratu Reservoir using Satellite Remote Sensing (SRS). The sedimentation assessment was carried out using satellite data and reservoir water level data from 2006 to 2012. Water spread area was analysed from satellite data. The Normalized Difference Water Index (NDWI) has been used to delineate open water features and to enhance the presence of water surface in satellite imagery of the Patratu Reservoir. Water spread area of the reservoir at a particular elevation on the date of the passing of the satellite was used to develop an elevation-area curve. For the present case, fluctuation of water level was found to vary from 387.096 to 406.152 m. The linear interpolation/extrapolation technique has been employed to assess the water spread area of Patratu Reservoir at different elevations. Further, these areas were used to compute the live storage capacity of the reservoir between two elevations by the Prismoidal formula. From the study, it was found that due to sedimentation, the live storage capacity of Patratu Reservoir has reduced from 101.95 to 89.96 hm3, thus showing capacity loss of 11.76% in a span of 44 years. To increase the live storage capacity of the reservoir it is proposed to adopt manual and mechanical digging combined with flushing for desilting of the deposited sediment.EDITOR D. Koutsoyiannis ASSOCIATE EDITOR S. Kanae

SEDIMENTATION STUDY IN A RESERVOIR USING REMOTE SENSING TECHNIQUE

Reservoir sedimentation is a severe problem faced by dams caused due to soil erosion which is almost immeasurable at source and occurs in the catchment areas of the reservoirs. The present study describes the evaluation of sedimentation carried out for Vaigai reservoir situated in Tamil Nadu, India. Vaigai reservoir nourishes the inhabitants through water storage and supply for irrigation and water power. Nowadays, capacity loss occurs in the reservoir due to sedimentation. As it is highly tedious and uneconomical to do hydrographic surveys, the frequentness in finding the sediment yield becomes impossible. But the recent application of remote sensing and GIS technologies in the field of Civil Engineering make it possible. The Satellite Remote Sensing (SRS) method for prediction of reservoir sedimentation uses directly the water-spread area of the reservoir at a particular elevation on the date of pass of the satellite. With known area and the difference in level of water, the capacity and thereby the loss in capacity of the reservoir due to sedimentation can also be estimated. This paper illustrates the prediction of sedimentation at Vaigai reservoir using remote sensing and ArcGIS.

Human interventions and consequent environmental degradation of a protected freshwater lake in Kerala, SW India

Sasthamkotta lake in the southwestern coast of India is the largest freshwater lake in the region. The lake has a water spread area of about 3.75 km2 and serves as a drinking water source for about seven lakh people in southern Kerala. Unfortunately, the lake is at the verge of severe degradation consequent to different kinds of human interferences. The Sasthamkotta lake receives water mainly from rainfall (2,350 mm/year) and surface run-off (3.33 million m3/ year). Apart from these, a significant quantity of water reaches the lake through underwater springs emerging from the Quaternary and Neogene aquifers as well. Rampant removal of construction grade sand using high power jet pumps from the Quaternary aquifers linking the lake with the adjoining river, over exploitation of lake water, unscientific engineering constructions, etc. are some of the externalities leading to degradation and ultimate drying up of the lake. The floodplain of the Kallada river, hosting the lake Sasthamkotta, was unaffected by sand extraction till early 1970’s. The results of the present study revealed that indiscriminate sand mining has turned floodplain area of about 3.57 km2 into fallow lands, during the past 3–4 decades. This together with the riverbed lowering due to instream sand mining has significantly reduced the groundwater replenishment of the lake system. The construction of embankment on the southern side of the lake has not only isolated the lake system from its natural settings, but has prevented the flood pulse contribution of monsoon waters to a considerable extent. The present paper examines in detail the pros and cons of the human induced environmental degradation of the Lake Sasthamkotta which is declared recently a Ramsar wetland of international importance. Based on the study, a set of recommendations are also drawn for improving the overall environmental quality of the Sasthamkotta lake in particular and the freshwater lakes in the coastal lands of densely populated tropics in general.

Super-resolution mapping of hyperspectral images for estimating the water-spread area of Peechi reservoir, southern India

Though the estimation of the water-spread area in reservoirs is often carried out by field surveys, it is time-consuming and tedious, and cannot be done periodically. To overcome this issue, satellite images are often used where the estimation is made through density slicing or conventional per-pixel classification. This results in an inaccurate estimation of reservoir capacity. The high cost and nonavailability of high-resolution images demands the use of an alternative approach that can give accurate information about the reservoir water-spread area. A hyperspectral image (Hyperion) of moderate resolution is used for the accurate estimation of the water-spread area of Peechi reservoir, southern India. The reservoir water-spread area obtained from per-pixel classification, subpixel classification, and super-resolution mapping approaches are compared with the water-spread area obtained from the ground truth hydrographic survey data. It is observed that the water-spread area estimated from the hyperspectral image by the per-pixel approach is 7.66 sq km, that by the subpixel approach is 6.34 sq km, and that by the super-resolution approach is 5.69 sq km compared to the actual area of 5.95 sq km. The classification accuracy estimated for the Hopfield neural network based super-resolution technique is 92.97%, whereas that for the conventional classifier (maximum likelihood) is 86.72%. This improved accuracy in classification resulted in an accurate estimation of water-spread area. Hence, it is inferred that super-resolution mapping applied to hyperspectral images is a computationally efficient approach for the accurate quantification of reservoir water-spread area.

IMPACT OF URBANISATION ON WATER QUALITY PARAMETERS – A CASE STUDY OF ASHTAMUDI LAKE KOLLAM

The Ashtamudi Lake in the Kollam District of Kerala lies in between 76.53°and 76.63° longitude and 8.93° and 8.83° latitude. It is a palm-shaped extensive waterbody with eight prominent arms, adjoining the Kollam town. This extensive estuarine system has a length of 16 km with a maximum width of 14 km and maximum depth up to 6.4m covering an area of 64.2 km 2 . The Ashtamudi Lake has been designated as a Ramsar Site (No.1204) in November 2002 and is also a major tourist place. It supports around 43-marshy mangrove species, 57-species of birds, 97-species of fishes and some unique copepod species which are important sources of food. More than 20,000 waterfowl visit the lake annually. Coconut husk retting, fishing, inland navigation and a fishing harbour at Neendkara are other benefits provided by this lake. The case study describes the effect of urbanisation on water quality parameters and suggest for its improvement. The water spread area for Ashtamudi Lake in these three years are found to be shrinking (1999 – 6424 ha, 2003 – 6140 ha, 2006 – 5734 ha). The detailed physico-chemical and biological examinations are collected for three years (1999, 2003, and 2006) made during pre-monsoon season for various locations and their average values are reported. A comprehensive plan is prepared to restore the water quality of Ashtamudi Lake near the Kollam City.

Assessment of Sedimentation in Major Reservoirs of Hard Rock Terrain of India Using RS Technique

Sedimentation in the reservoir reduces the storage capacity and its life. Hence, the periodic investigation is necessary to arrive at a realistic siltation index for planning of future reservoir projects in the basin. The conventional techniques of sediment quantification in a reservoir are cumbersome, costly and time consuming. With the advent of remote sensing techniques, it has become very cheap and convenient to quantify the amount of sedimentation in the reservoir. Therefore, in the present study, the assessment of the sedimentation in major reservoirs of hard rock terrain was carried out using the digital image processing of remotely sensed data of reservoirs in hard rock terrain of India. The remote sensing data acquired for various dates were analysed for estimating the reservoir water spread area as well as computing the capacity of reservoir. The annual rate of sedimentation and further loss in reservoir capacity are found more in case of Tungabhadra reservoir as compare to other reservoirs under study due to its drainage characteristics. The revised Elevation-Area-Capacity (EAC) curves developed for study reservoirs will be helpful to reservoir authority for planning the mitigation measures to enhance the capacity and its operation. The factors related to catchment characteristics influencing reservoir sedimentation were also analysed. Based on the analysis, it can be revealed that the rate of sedimentation is linearly correlated with size of the drainage area. KeywordsReservoir Sedimentation; Reservoir Capacity; Remote Sensing; Digital Image Processing

Sustainable Management of Malwathu Oya Cascade-I: Present Status and Future Needs

Village tank cascade System is an old age art of irrigation technology presence, especially in North Central dry zone of Sri Lanka. Some of these cascades were already evaluated but most of them are not yet. In Malwathu Oya Cascade-I, no any comprehensive study was carried out yet, therefore this study aimed conduct a comprehensive study of Malwathu Oya cascade-I including demarcation of meso and micro catchments of this cascade, understanding of characteristics and hydrological endowment of the cascade, estimating tank water storage, runoff and irrigation water demand etc. Catchment, water spread and commanding areas of the individual tanks were measured and tank storage, effective runoff to tanks, irrigation water demand and cascade outflow were estimated. With the results, cascade was evaluated for hydrological endowment of the cascade, cascade water surplus and potential water availability. Malwathu Oya cascade-I is a branched type large cascade with the form index of 3.6. The total area of the cascade is 25.88 square kilometers with overall length of 7.1 kilometers. Total water spread area of the tanks and total commanding area of the tanks are 2.57 and 2.81 square kilometers respectively. Tank water supply adequacy showed that, cascade has adequate source of water to cater the irrigation requirement of the command area. All the individual tanks in the cascade except Kudawewa, Palugaswewa and Sattambikulama showed adequate storage capacity. According to the ratio of cascade area to the total tank water surface area of the cascade and ratio of cascade command area to the total tank water surface area, the cascade can be identified as a cascade with good hydrological endowment and stability. According to the cropping intensity of the cascade, cascade can be categorized as a well performing cascade.

Analysis of Land Use/Land Cover Changes Using Remote Sensing Data and GIS at an Urban Area, Tirupati, India

Land use/land cover (LU/LC) changes were determined in an urban area, Tirupati, from 1976 to 2003 by using Geographical Information Systems (GISs) and remote sensing technology. These studies were employed by using the Survey of India topographic map 57 O/6 and the remote sensing data of LISS III and PAN of IRS ID of 2003. The study area was classified into eight categories on the basis of field study, geographical conditions, and remote sensing data. The comparison of LU/LC in 1976 and 2003 derived from toposheet and satellite imagery interpretation indicates that there is a significant increase in built-up area, open forest, plantation, and other lands. It is also noted that substantial amount of agriculture land, water spread area, and dense forest area vanished during the period of study which may be due to rapid urbanization of the study area. No mining activities were found in the study area in 1976, but a small addition of mining land was found in 2003.