8. Unit-V GIS Applications

UNIT-V : APPLICATIONS OF GIS

Resource mappingGroundwaterFlood monitoring & Wetland managementForrest managementLanduse and Landcover analysisRegional and Urban planningGeology Agriculture and soilIntegration with Remote Sensing

04/22/23 1Unir-V Application of GIS - T. Magendran

Resource mapping

• A resource is a source or supply from which benefit is produced

• Resource mapping – An approach to delineating, measuring,

monitoring, and analyzing the natural resources by the aspects of GIS with feature mapping and object-based classification

04/22/23 Unir-V Application of GIS - T. Magendran 2


Methodology for GIS data

Processing


Methodology for GIS data

Generation of thematic maps

Groundwater


RS & GIS for GW exploration identification of artificial recharge sites

• Aim & Objectives– To extract information on the hydrogeomorphic

features of a hard rock terrain– Designing a suitable groundwater management

plan for a hard rock terrain– To exhibits reservoir induced artificial

groundwater recharge downstream of surface water reservoirs.


Datasets used• Remotely-sensed data, viz. IRS-LISS-II

• Existing maps, viz. Survey of India (SOI) Toposheets

• Published geological map.

• Field data, viz. depth to water level data of 18 dug wells (CGWB 1980)

• Pre- and post-monsoon data for three years consecutively from 1976 to 1978 are used to determine the nature of movement of groundwater in the area.


Met

hodo

logy


• IRS-LISS-II FCC (750 pixels by 750 pixels) (bands 432 in RGB scheme) depicts reservoir induced recharge and better groundwater conditions along valley fills. Anomalous growth of vegetation along valley fills and down stream of reservoirs indicates improved groundwater conditions, the general direction of groundwater flow and the extent of reservoir induced recharge.



Three-dimensional perspective view of the study area

• Lineament map of the study area based on IRS-LISS-II data analysis and field information. Rose diagram (Inset) shows the general trend of the lineaments present in the study area.


• Drainage network superimposed over the DEM of the study area. Lighter tones in the DEM depict higher ground, whereas darker tones indicate lower ground.




Suitable sites for artificial recharge


Conclusion • This study has enabled an evaluation of the capabilities of IRS-LISS-II data

for comprehensive understanding of the groundwater conditions of a hard rock area.

• Digital analysis of LISS-II data has permitted identication of groundwater recharge due to reservoirs in the study area.

• This is further augmented by analysis of thematic information derived from DEM and groundwater data in a GIS environment.

• Integrated analysis provides a further insight into the hydrogeological regime of the area which can be utilized for site selection for articial recharge.

• GIS facilitates conjunctive analysis of multi-parameter thematic data and decision making for efficient planning for groundwater management.

• The spatial database developed during this study is being improved by adding further information layers and a modelling approach may be adopted in future using integrated GIS.




04/22/23 19Well locations and value range of specific capacity (SPC) in the study area.

Unir-V Application of GIS - T. Magendran

04/22/23 20Hydrogeological units extracted from geological map of study area.Unir-V Application of GIS - T. Magendran

04/22/23 21(a) and lineament distribution from Landsat TM image (b) of study area.

Unir-V Application of GIS - T. Magendran

04/22/23 22Groundwater potential map for specific capacity (SPC)Unir-V Application of GIS - T. Magendran

Flood Monitoring &

Wetland Management



Definitions

Floods

A great flow of water; a body of moving water; the flowing stream, as of a river; especially, a body of water, rising, swelling, and overflowing land not usually thus covered; a deluge; a freshet; an inundation.

Flash floodsA flash flood is a sudden inundation of water in low-lying areas, usually brought on by heavy rain or a dam break.


What are different types of flooding?

River flooding: River flooding occurs when heavy rains or rapid snowmelt cause rivers to rise. Coastal flooding: Coastal flooding may occur due to tidal surges and flash flooding. Flash Floods: Flash floods usually result from intense storms dropping large amounts of rain within a brief period. Dam Failure:Dam failures are potentially the worst flood events. When a dam fails, a gigantic quantity of water is suddenly let loose downstream, destroying anything in its path.


Causes of floods

Storm

Heavy rainfall

Sudden melting of snow and ice in mountain areas

Failure of a construction in the water system (dike, sluice,

weir)


World Flood Map




Flood risks in India


Floods in Mumbai

Effects of floods

The main effect of the floods is SOIL EROSION. Floods take away the upper fertile layer of soil with it and instead brings with it the unfertile clay.Floods uproot the trees which keep environment ecologically safe Floods make an enormous impact on the environment and society. Floods destroy drainage systems

Benefits of flooding

However, floods (in particular the more frequent/smaller floods) can bring many benefits, such as recharging ground water, making soil more fertile and providing nutrients in which it is deficient.

Flood waters provide much needed water resources in particular in arid and semi-arid regions where precipitation events can be very unevenly distributed throughout the year.

Prevention of floods

The creation of flood plains and winding streams are two of the best ways to hinder the accumulation of water by providing a route for the drainage of water

Levees also impede the collecting of water. Levees are embankments composed of soil and earthen material that are used to prevent

annual flooding in many areas.

FORMATION OF NATURAL LEVEES

Flood Watch...

This means that flooding is possible with the watch area. You should remain alert and be ready to evacuate on a moment's notice.

Flood Warning...

This means that flooding has been reported, or is imminent. When a flood warning is issued for your area, act quickly to save yourself.

Go to higher ground, or climb to safety. Move to a safe area before access is cut off by rising flood waters.

Integrated Flood Management

Flood Management in the context of Integrated Water Resources Management, aiming at:

Sustainable development: Balancing development needs and flood risksMaximizing net benefits from floodplains: Ensure livelihood security and poverty alleviation thereby reducing vulnerability Minimizing loss of life:

In particular through end-to-end FF&W Systems and preparedness planning for extreme events Environmental preservation: Ecosystem health & services

New challenges!

Increasing Flood Risks

Absolute safety against floods is a myth

Climate change uncertainty

Growing environmental concerns

IFM: Principles

•Mitigation and Preparedness•Response•Recovery and rehabilitation•Residual risks

IFM: Principles

1. Risk Management2. Water Cycle as a whole

– Flood and drought management

– Effective use of flood waters– Ground water and surface water interaction in flood plains

3. Multi-hazard approach4. River basin as a planning unit

List of deadliest floods

Flood Management

• Out of the country's total geographical area of 329 million hectare, about 40 million hectare is prone to floods.

• Till March 2007, an area of 18.22 million hectare has been provided with protection against floods by way of construction of embankments, drainage channels, town protection works and raising on platforms.

Flood Management

• In order to mitigate the damages from floods, a nation wide Flood Forecasting and Warning System has been established by the Central Water Commission on interstate river basins and flood forecasts are being issued through 175 Stations, out of which 147 are river level forecasting Stations and 28 are inflow forecasting stations on major dams/reservoirs.

Flood Management

Forecasts about

– water levels in rivers likely to be attained as a result of floods

– volume of inflow into reservoirs

are formulated and disseminated to various administrative authorities of Central Government, State Government and District Administration, media and other users on the basis of real time data.

Role of satellite images in flood inundation studies

Before and After Landsat Imagery for the Mississippi Flood of 1997(Photo Courtesy of Space Imaging EOSAT)

Softwares used for flood related studies

• ArcGIS Hydro Data Model

• GIS Stream Pro

• RiverCAD

Flood warning systemThe Brihanmumbai Municipal Corporation (BMC) will install an automatic flood warning system for Mumbai by the monsoonof 2006. The system will consist of electronic rain gauges rigged to send alarm signals to a central control room in the event of a rise in the water level.

Wetland Management



Methodological flow of the process involved in linking ecological and socio-economic variables.

Forrest management




Landuse and Landcover analysis

Land use

• Land use is the human use of land

• Land use involves the management and modification of natural environment into built environment such as fields, pastures, and settlements.


Land cover


• Land cover is the physical material at the surface of the earth. – Land covers include grass, asphalt, trees, bare

ground, water, etc.

• There are two primary methods for capturing information on land cover: – field survey and – analysis of remotely sensed imagery.




Regional and Urban planning


Urbanization – Urban developemnt

• Migration of rural population to urban area– Dynamic phenomena


- A case study from Dehradun city



• In order to identify the sites for urban growth certain factors to be considered,– Land should be vacant or having low usage value

presently– Appreciable distance from river – to avoid flood

hazard– Proper accessibility– More or less flat land– Good supply of water






6604/22/23 [email protected]

Documents

8. Unit-V GIS Applications