Watershed delineation for Hydropower project

Watershed delineation to propose a hydropower project in Shoghor-Chitral • • • •

Aamir Zaman Aqeel Tariq Azeem Zafar Mudassar Sarwar

Content • Introduction • Objective • Site description • Methodology • Recommendations

Study Area • 36.02.01N – 71.33.20E • Altitude 3700ft • Shoghor-Chitral • Mountainous area • Chitral River • Glaciers

• Energy source • Kerosene oil till 80s • 1990 Micro Hydel Projects (AKRSP)

Objective Purpose of our analysis was to calculate watershed delineation to propose a suitable site for a hydropower project.

Requirements • ArcGIS - Arc Hydro • Data Elevation Model • Satellite Imagery • Physiography • Regional Geological and Tectonic Setting • Site Stratigraphic Information

General Geology • Rock types • Metamorphic • Chitral Slate (Slates, Phyllite, Siltstone)

• Tectonically Less active

ACQUISITION OF POINT DATA

DEM Set up ARCGIS working environment

FILL

FLOW DIRECTION

FLOW ACCUMULATION

STREAM NETWORK

STREAM LINK

WATERSHED DELINEATION

Why we choose 10m DEM? • 30m DEM generally flows within the valley but deviates from actual channel location. • 10m DEM produce much realistic flow paths that follow the channels.

Fill DEM • The Fill sinks operation removes local depressions from a DEM by replacing these local depressions by flat areas in the output DEM.

Fill DEM • Depressions that consist of a single pixel.

• Find a sink that consists of a single pixel (pixel in red).

• Assign to this pixel, the smallest value found among its 8 neighbor pixels (pixel in green).

Fill DEM • Depressions that consist of multiple pixels.

• outlet for this depression is determined.

• the height values of this depression will be increased to the smallest height value of a pixel.

• that is adjacent to the outlet for this depression/sink, and that would contribute to the initial sink

• Pixels at the border of the map are never changed.

Fill DEM

Flow Direction • focal function • Flow direction operation determines into which neighboring pixel any water in a central pixel will flow.

• Flow direction is calculated for every central pixel in input blocks of 3 by 3 pixels, each time comparing the value of the central pixel with the value of its 8 neighboring pixels.

• The output map contains flow directions as N (to the North), NE (to the North East), etc.

Flow Accumulation • The Flow accumulation operation determines the number of pixels that naturally drain into outlets. • The output map contains cumulative hydrologic flow values that represent the number of input pixels which contribute any water to the outlets (or sinks if these have not been removed).

Result of Flow accumulation. Result of Flow accumulation when Fill sinks is not used.

Stream Network • Stream networks are delineated from a digital elevation model (DEM) using the output from the Flow Accumulation function. • Flow accumulation in its simplest form is the number of upslope cells that flow into each cell.

Stream Link • The Stream Link function allows you to assign unique values to each of the links in a raster linear network.

Watershed Delineation • Flow direction and stream link are use to delineate watershed.

Recommendations • Large amount of glacial water wasted.

• Area is also in Energy crises.

• Foundation conditions are favorable for construction of the hydropower projects • Pouring point of whole area is in SHOGHOR. • Hydro power potential of this river is modest but it can fulfill the needs of the locals.

Gracias!