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GIS application in hydrogeological studies

S.Thiruvengadachari
Senior GIS Expert, Consultant, Hydrology Project, World Bank
charist@hd2.dot.net.in


The on-going World Bank assisted Hydrology Project (HP) aims at assisting the Central Government and the participating eight peninsular States in the development of valid, comprehensive, interactive, easily accessed, and user friendly data bases

The Mid Term review Mission of the World bank has approved the enhancement of the Hydrological Information system with GIS data sets, to provide the spatial dimensions to the point measurements of surface and groundwater quantity, quality and hydrometeorology. The on-going World Bank assisted Hydrology Project (HP) aims at assisting the Central Government and the participating eight peninsular States in the development of valid, comprehensive, interactive, easily accessed, and user friendly data bases covering all important aspects of the hydrological and meteorological cycle; and to provide such data to all legitimate users involved in water resources management. The water resources agencies in the participating States of Andhra Pradesh, Gujarat, Karnataka, Kerala, Madhya Pradesh, Maharashtra, Orissa, and Tamil Nadu are in the process of improving and expanding the observation network, water quality laboratories and computing facilities for collection, compilation, validation and archival of point measurements of hydrometeorological and hydrological parameters.
>BR> The GIS technology will enable to relate point measurements to administrative and hydrologic units, generate customized maps, query the database and use the data in modeling applications. Building GIS capability in the Hydrology Project covers:
  • Hardware and GIS modules in surface water (SW) and groundwater (GW) data processing software in all participating States, and stand-alone GIS systems in Andhra Pradesh, Maharashtra and Orissa States.
  • Generating minimum spatial data sets relevant to SW/GW hydrology in all participating States.
  • Hydrometeorology/surface water/groundwater measurements referenced to SOI map coordinates and datum.>
  • Upgrading skills through training for managers and specialists.
The basic infrastructure for GIS hardware and software is currently being implemented under the Hydrology Project. The dedicated Surface Water Data Processing software (HYMOS) and the dedicated Groundwater Data Processing (GWDP) software proposed under the Hydrology Project will have GIS functionality. The GWDP software will also have additional modules for water balance and resource assessment, which call for appropriate spatial data sets. The SWDPS also has provision to process, compile and store spatial data on basin characteristics and location data on observation stations and hydraulic structures. Necessary computers and peripherals are being procured.

The proposed GIS strengthening covers preparation of GIS data sets by GW departments in participating states, and provision of stand-alone computer hardware and GIS software and support training in Maharashtra, Orissa and Andhra Pradesh States.

A major exercise has now been initiated under HP to generate minimum spatial data sets in the 8 participating States. The overall approach is shown in Fig.1 along with the proposed time schedule.

Objective and Scope
To generate GIS data sets on select themes for integration in the surface and groundwater Data Centres in 8 participating states, and in the National Data centres.

The State Groundwater agency will have responsibility within each state for generating and distributing spatial data sets to the State Surface Water agency, Central Water Commission and Central Ground Water Board. A State Level Technical Committee will be constituted to support the activity. The Technical Committee may have representatives from the State surface and groundwater agencies, the Central Ground Water Board, the Central Water Commission, the Survey of India and the Geological Survey of India.

The State GWD will provide a copy of GIS data sets to the surface water agency for integration in the State Surface Water Data Centre. Surface water and groundwater agencies in each state will integrate data in their respective Data Centres.

The Central Water Commission and Central Ground Water Board will be responsible for the integration of GIS data sets from all 8 States into the National Surface and Ground water Data Centres.


Fig. 2: Primary Data Layers

The generation of GIS data sets will be outsourced to vendors through a competitive bidding procedure, independently by each participating State GWD. To ensure uniformity and consistency in data sets, the standard methodology specified by the Hydrology Project will be followed by the vendors and rigorous quality control will be exercised. The generation of digital spatial data sets covering about 2600 map sheets in 1:50,000 scale over 8 participating states should be completed before the second quarter of 2001, with subsequent integration in the Data Centres during the balance period of HP.

Selection of GIS Data Sets
The selection of minimum GIS data sets will be guided by the relevance and commonality to both the surface and groundwater components of HP. Surface water analysis requires a minimum set of thematic data on land use, soil, topography and drainage, while ground water analysis will additionally require spatial data on geology (lithology/ rock type and structure) and geomorphology. General supporting data cover settlements, transport network and administrative boundaries. This only constitutes a minimum spatial data set, considering the time and manpower constraints. For example, data on irrigation command areas, canal network and other water use sectors such as industries, though useful, will be difficult to generate within the balance period of HP.

The suggested themes in 1:50,000 scale are: land use/cover (including surface water), soil, geology (lithology/rock type and structure) and geomorphology (to be derived from satellite data), and drainage patterns, settlements, contours and spot heights, and transportation network from the most current Survey of India topographic maps (Fig 2). It is envisaged that a minimum data set will be augmented by additional spatial data sets in the course of time, to meet fresh analysis requirements.

Inventory of Existing Spatial Data Sets and Fresh Generation Requirements
The extent of fresh data generation requirements will be assessed based on the inventory of existing data sets in map and digital format, generated under national and State programmes. The existing data sets will be reviewed under a set of standard criteria (thematic classification scheme, mapping and thematic accuracy, age of data and availability) for acceptance in HP. Additional fresh generation of data sets (thematic mapping and digitization, digitization of existing maps and format conversion of existing digital data sets) will be defined for each state. The preparation of these data sets will be as per the standard methodology proposed by HP, to ensure consistency and uniformity amongst the participating States.

A High Level Technical Group (HLTG) will approve the selection of primary themes and classification schemes, methodology manual, bidding procedure and document, and integration of GIS data sets into National and State Data Centres. The State Level Committee may have representatives from the State Ground Water Department, Surface Water Agency, Central Water Commission, CGWB, Survey of India, GSI and the State Remote Sensing Centre. The Committee will support the State GWD in conducting the inventory of existing GIS data sets, defining fresh data generation requirements, external quality audit of data products, and integration of GIS data sets into the State Data Centre.

Standard Methodology for Generating Data Sets
The methodology will cover i) fresh thematic data generation, ii) digital conversion of fresh and existing thematic maps and select details from SOI maps, and iii) format conversion of existing digital data set.

It is proposed to procure services from a large number of vendors in the preparation of spatial data sets. The manual provides technical guidelines for preparation of uniform and consistent spatial data sets by multiple vendors, by standardizing the methodology and input and output products.

The manual provides an overview of spatial data sets: selected themes, input data, output data and generation methodology, and the spatial database organization (including map tiles and TIC mark Ids) and data specifications in regard to scale, map projection, digitization accuracy, and registration accuracy between layers. Theme-wise chapters cover the classification scheme, input data specifications, methodology flowchart, feature coding standards, output file naming convention, internal QC and external QA, and specifications for deliverable products.

Annexures of the manual describe how the classification and map accuracy is estimated, the standard procedure for digitization, the internal quality control and external quality audit procedure, and provide details of the report accompanying each digital map tile including the QC/QA statement (map tile code, generation date, mapping accuracy, thematic accuracy, and digitization accuracy); brief description of input data, generation procedure, and output products; and contact address in vendors office for future follow-up.

Procedure for Generating Data Sets
The Ground Water department of each participating State will be responsible for generating data sets within the State. The data sets will be produced through outsourcing to vendors through a competitive bidding procedure.

A State Level Technical Committee consisting of representatives from the State surface and ground water agencies, Central Water Commission and Central Ground Water Board will support the State GWD. It is recommended to include the Geological Survey of India (GSI) for i) technical inputs on geology related themes and ii) to facilitate procurement of data sets from the National Geoscientific Data Centre developed under GSI-BRGM Project. The Technical Committee will provide guidance and support on defining fresh spatial data generation, external independent quality audit of data products and integration of spatial data sets into the State Surface and Groundwater Data Centres.

The HLTG will oversee all the generic aspects such as selection of minimum GIS data sets, standard methodology to be followed, bidding procedure including vendor qualification by appropriate weighting, and integration of GIS data sets into the State and National Data Centres.

Inventory of Existing Spatial Data Sets and Fresh Generation Requirements
The extent of fresh data generation requirements will be assessed based on the inventory of existing data sets in map and digital format, generated under national and State programmes. The existing data sets will be reviewed under a set of standard criteria (thematic classification scheme, mapping and thematic accuracy, age of data and availability) for acceptance in HP. Additional fresh generation of data sets (thematic mapping and digitization, digitization of existing maps and format conversion of existing digital data sets) will be defined for each state. The preparation of these data sets will be as per the standard methodology proposed by HP, to ensure consistency and uniformity amongst the participating States.

A High Level Technical Group (HLTG) will approve the selection of primary themes and classification schemes, methodology manual, bidding procedure and document, and integration of GIS data sets into National and State Data Centres. The State Level Committee may have representatives from the State Ground Water Department, Surface Water Agency, Central Water Commission, CGWB, Survey of India, GSI and the State Remote Sensing Centre. The Committee will support the State GWD in conducting the inventory of existing GIS data sets, defining fresh data generation requirements, external quality audit of data products, and integration of GIS data sets into the State Data Centre.

Standard Methodology for Generating Data Sets
The methodology will cover i) fresh thematic data generation, ii) digital conversion of fresh and existing thematic maps and select details from SOI maps, and iii) format conversion of existing digital data set.

It is proposed to procure services from a large number of vendors in the preparation of spatial data sets. The manual provides technical guidelines for preparation of uniform and consistent spatial data sets by multiple vendors, by standardizing the methodology and input and output products.

The manual provides an overview of spatial data sets: selected themes, input data, output data and generation methodology, and the spatial database organization (including map tiles and TIC mark Ids) and data specifications in regard to scale, map projection, digitization accuracy, and registration accuracy between layers. Theme-wise chapters cover the classification scheme, input data specifications, methodology flowchart, feature coding standards, output file naming convention, internal QC and external QA, and specifications for deliverable products.

Annexures of the manual describe how the classification and map accuracy is estimated, the standard procedure for digitization, the internal quality control and external quality audit procedure, and provide details of the report accompanying each digital map tile including the QC/QA statement (map tile code, generation date, mapping accuracy, thematic accuracy, and digitization accuracy); brief description of input data, generation procedure, and output products; and contact address in vendors office for future follow-up.

Procedure for Generating Data Sets
The Ground Water department of each participating State will be responsible for generating data sets within the State. The data sets will be produced through outsourcing to vendors through a competitive bidding procedure.

A State Level Technical Committee consisting of representatives from the State surface and ground water agencies, Central Water Commission and Central Ground Water Board will support the State GWD. It is recommended to include the Geological Survey of India (GSI) for i) technical inputs on geology related themes and ii) to facilitate procurement of data sets from the National Geoscientific Data Centre developed under GSI-BRGM Project. The Technical Committee will provide guidance and support on defining fresh spatial data generation, external independent quality audit of data products and integration of spatial data sets into the State Surface and Groundwater Data Centres.

The HLTG will oversee all the generic aspects such as selection of minimum GIS data sets, standard methodology to be followed, bidding procedure including vendor qualification by appropriate weighting, and integration of GIS data sets into the State and National Data Centres.

Preparation of Bid Document
A generic bid document will be prepared by the Consultants, and approved by HLTG for adoption by the State GWDs. The bid document will specify data generation requirements, methodology to be followed and qualification of vendors as part of the evaluation procedure. Particularly important is the qualification of vendors by assigning weights to financial strength (annual turnover) to undertake the large job, years of experience in the mapping and digitization activity, experience in multi-theme mapping in the same region, adequate computer hardware and software, supporting facilities such as soil lab, trained manpower (academically qualified, previous experience in thematic mapping) and certification of successful completion of past work. Selection of qualified vendors by weighting is essential in view of past experience where unqualified vendors were selected based on lowest quotation, and work was not completed successfully.

Bids will be invited for a ‘minimum lot’ of data sets (perhaps regional coverage of all themes which is cost effective from field visit angle, and ensures internal consistency between themes and theme matching across map sheets). The proposed internal QC procedure (at different stages of data set preparation) needs to be detailed by the bidder.

Joint Ventures between bidding companies (with the responsibilities of each agency to be listed) will be encouraged so that the whole State or a large region within the State is covered by one such group. The bid would include penalty clauses for delayed delivery and poor map quality.

Bid Evaluation and Issue of Order
The responses received from vendors will be evaluated as per the weighting procedure defined in the bid document, and the successful bidder will be identified for issue of order.

External Quality Audit and Acceptance of data sets from vendor
Generation of standard and consistent data sets by multiple vendors in different locations requires that rigorous quality control is exercised internally and through independent external audit. Internal Quality Assurance procedures will cover different critical stages in data set generation, starting from appropriate satellite and other map input data selection, thematic interpretation and validation, and final map validation. The stages in the digitization process will cover scanning and digitization, labeling and attribute tables, and product labeling and reporting. Quality assessment will involve both visual inspection and measurements. The vendor will develop a comprehensive QA procedure and report compliance. In addition to the internal QC of the selected vendor generating the data set, an independent quality audit by the State GWD is proposed at specific stages of data set generation. While internal QA will cover each data product, external QA will be on sampling basis.

A checklist of parameters to be assessed at each stage will be prepared and completed and attached to the report accompanying the product. For example, the data selection assessment will involve the parameters of year and seasons of satellite data, sensor, and area coverage corresponding to specified SOI map.

The QC report will also be accessible to the external QA team during visits to the vendor site. The products delivered by the contract agency will be accepted by the State GWD when they satisfy the criteria defined in the bid document.

Integration of Spatial Data Sets in the Data Centres
The State GWD will be responsible for the integration of spatial data sets in the State Ground Water Data Centre, and for providing a copy of the data sets to the State surface water agency, which in turn will be responsible for integration in the State Surface Water Data Centre.

The State GWDs will also provide a copy of data sets to the Central Water Commission and Central Ground Water Board, for integration in the respective National Data Centres.

Conclusions
The generation and integration of spatial data sets in the national and State Data Centres will provide the spatial dimension to the point measurements made under the Hydrology Project. Considering the importance of these data centres all care need to be taken to generate authentic, reliable and accurate data. Any inclusion of existing data shall be only when the data specifications are satisfied, and fresh generation shall ensure the highest data quality.

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