Surface Water modelling using Remote Sensing


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Surface Water modelling using Remote Sensing. It uses curve number method

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Surface Water modelling using Remote Sensing

  1. 1. ARJUN GANGADHARAN 3rd year Civil Engineering RVS Faculty of Engineering Coimbatore
  2. 2. The Art or Technique or Science of obtaining reliable information about the physical objects and the environment through the process of recording, measuring and interpreting imagery and the digital representation of energy pattern derived from non contact sensor system
  3. 3. SourceObject SatelliteGround station
  4. 4. As you view an object, you areactively engaged in remote sensing. Aphysical quantity (light) emanatesfrom the object, which is a source ofradiation. The radiated light passesover a distance, and thus is "remote"to some extent, until it encountersand is captured by a sensor (youreyes). Each eye sends a signal to aprocessor (your brain) which recordsthe data and interprets this intoinformation.
  5. 5. Proper management of surfaceand ground water resources is animportant step against waterscarcity.Runoff estimation based onrainfall is the first step in watermanagement.Based on United StatesDepartment of Agriculture (USDA)Soil Conservation Service (SCS)Method the runoff calculation isdone.
  6. 6. The Survey of India (SOI) Topographic maps for the demarcation of the watershed line.The rainfall data from Meteorological Department.The land use and land cover map prepared from satellite imagery.The drainage map prepared from SOI Topographic sheetThe soil information was collected from the Soil Survey of India
  7. 7. 1. Land cover/land use classification2. Trend analysis3. Ground water flow system study4. Rainfall – runoff modelling methods5. Rainfall runoff-soil conservation system-curve number method6. Hydrogeological evaluation and mapping7. Hard rock terrain and lineaments analysis8. Thermal imagery study9. Soil types analysis
  8. 8.  SCS-CN theory is based on the fact that direct runoff depends on land cover, land use, soil type and antecedent moisture conditions of surface soil. Several accompanying tables had been developed in association with empirical equations Applying SCS method on a large area, with variant specifications, would be almost impossible if done manually. Regarding this matter, an automated computer model is needed to achieve desired accuracy. SCS rainfall runoff model, developed by United States Department of Agriculture (USDA) provides an empirical relationship estimating initial abstraction and runoff as a function of soil type and landuse.
  9. 9. 1.The water balance equation is expressed by Q = P – (Ia+ F)2.Estimation of rainfall runoff using SCS-CN model is defined by3.For Indian soil condition the above relation is modified as and 4.The SCS rainfall runoff model is modifiedto include parameter – watershed area, slope,drainage length, and land cover. The equationfor average runoff Qa is defined by
  10. 10. The Curve Number (CN)is an index developed bythe Natural ResourceConservation Service(NRCS), to represent thepotential for storm waterrunoff within a drainagearea.
  11. 11. The data and analysis reports can be used in modelling.It gives a clear picture of the nature of runoff in the study area.The study report can be made use for the feasibility studies for theconstruction on reservoirs or dams.The method can be employed in the efficiency study of thecatchment.With results we can estimate the total volume of runoff volume thearea, which is employed in many other studies such as predicting theflood areas during monsoon.The water scarcity of the area can be minimized by theconstruction of rain water sheds/tanks.The suitable locations for dams and reservoirs can be obtained insuch a way that the maximum runoff volume is collected by it.Remote sensing and GIS techniques allow such analysis toperformed in a short time, at high accuracy and low costs.
  12. 12. Thank You ! 