Delineating watershed using QGIS

 

3.1             QSWAT

Install QSWAt and launch it from plug in

Click on new Project after saving,  select delineate watershed from the new popup window

This will ask you to select a DEM 

Now determine the sub watershed size either by setting the the number of pixels or the area in hectare or sq km

After determining the size click on create streams

the streams created and appear in the canvases as follow

Add your outlet (The red one) what you want to delineate / a point obtained from field

Select draw inlet/outlet

the cursor will be ready to add a point to your watershed delineation database. 

 and click on a stream which is closer to your outlet. this will make a point with blue triangle symbol as an outlet for the watershed delineation 

Then click ok 

Click on “select  inlet/outlet” and select the outlay you draw in the previous step you can select many outlets by using shift key

Click exactly on the out let (with blue color) created  to be sure the color will be changed to yellow to indicate he outlet is selected 

after selecting the outlet, click on save then it says one feature select

Finally click on create a watershed icon

the watershed with its sub micro watershed will be produced!

In order to avoid micro watersheds

•        Open attribute Table è Select All

•        Save the dialogue box

•        Merge

 

 

Connect Google Map to QGIS

 

  Connect Google Map  to QGIS

o   Go to Browser panel 

o   right click on XYZ

o   Select new connection

       Give a name to the connection as you wish in our case Google Map

and    Use either of  the following links   When appropriate

                                    I.        Google Maps: https://mt1.google.com/vt/lyrs=r&x={x}&y={y}&z={z} 

                                   II.        Google Satellite: http://www.google.cn/maps/vt?lyrs=s@189&gl=cn&x={x}&y={y}&z={z}

                                 III.        Google Satellite Hybrid: https://mt1.google.com/vt/lyrs=y&x={x}&y={y}&z={z}

                                 IV.        Google Terrain: https://mt1.google.com/vt/lyrs=p&x={x}&y={y}&z={z}

                                  V.        Google Roads: https://mt1.google.com/vt/lyrs=h&x={x}&y={y}&z={z}

o   To connect with Google map use the second link as shown bellow ( be sure not to leave space at the end of the link while pasting)

 Here it is 

Soil And Water Conservation : When to apply

 

·         CONSERVATION MEASURES ON CULTIVATED LAND

o   Alley Cropping 

§  Slope Range: All

§  Soil Range: All, including shallow and

§  degraded soilsMoist and Wet Dega

§  Moist and Wet Weyna Dega

§  Moist and Wet Kolla

§  Moist Berha

o   Bench Terrace  60

§  Slope Range: Slopes with gradients up to 50%

§  Soil Range: Vertical interval is two-and-a-half times the

§  soil depth

§  All High Dega

§  All Dega

§  All Weyna Dega

§  All Kolla

§  Moist Berh

o   Broadbed and Furrow  62

§  Slope Range: Gentle slopes of less than 15%

§  Soil Range: Heavy soils, e.g. Vertisol

§  All High Dega

§  Moist and Wet Dega

§  Moist and Wet Weyna Dega

§  Moist and Wet Kolla

§  Moist Berha

o   Conservation Tillage  64

§  Slope Range: All slopes (above 15%, however, combine

§  with contour structures)

§  Soil Range: All

§  All High Dega

§  All Dega

§  All Weyna Dega

o   Graded Bund  66

§  Slope Range: 3–50%

§  Soil Range: All soils in wet, clay soil in moist

§  agro-ecological zones

§  All High Dega

§  Moist and Wet Dega

§  Moist and Wet Weyna Dega

§  Moist and Wet Kolla

§  Moist Berha

o   Graded Fanya Juu  68

§  Slope Range: 3–50%, more on steeper slopes

§  Soil Range: All deep soils in wet, deep clay soils in

§  moist agroecological zones

§  All High Dega

§  Moist and Wet Dega

§  Moist and Wet Weyna Dega

§  Moist and Wet Kolla

§  Moist Berha

o   Grass Strip 

§  Slope Range: Slopes with gradients of less than 15%

§  Soil Range: All

§  All High Dega

§  Moist and Wet Dega

§  Moist and Wet Weyna Dega

§  Moist and Wet Kolla

§  Moist Berha

o   Level Bund 

§  Slope Range: 3–50%

§  Soil Range: All depths greater than 50 cm, or

§  according to farmer’s consent

§  Moist High Dega

§  Dry and Moist Dega

§  Dry and Moist Weyna Dega

§  Dry and Moist Kolla

§  Moist Berha

o   Level Fanya Juu  74

§  Slope Range: 3–50%

§  Soil Range: All depths greater than 50 cm, according

§  to farmer’s consent

§  Moist High Dega

§  Dry and Moist Dega

§  Dry and Moist Weyna Dega

§  Dry and Moist Kolla

§  Moist Berha

o   Mulch  76

§  Slope Range: All (combined with contour structures on steeper slopes)

§  Soil Range: All, in particular shallow and

§  degraded soils, but less suitable on heavy soils where  waterlogging is a problem

§  All Dega

§  All Weyna Dega

§  All Kolla

§  Moist Berha

o   Trash Line  78

§  Slope Range: Gentle slopes of less than 15%

§  Soil Range: All

§  All Dega

§  All Weyna Dega

§  All Kolla

§  Moist Berha

o   Vetiver  80

§  Slope Range: All

§  Soil Range: All

§  All Dega

§  All Weyna Dega

§  All Kolla

§  Moist Berha

·         CONSERVATION MEASURES ON GRASSLAND

o   Controlled Grazing 

§  Slope Range: On gentle, well-covered rangeland

§  Soil Range: All except heavily degraded soil

§  All High Dega

§  All Dega

§  All Weyna Dega

§  All Kolla

§  Moist Berha

o   Cut and Carry 

§  Slope Range: After grass established, all slopes

§  Soil Range: All except heavily degraded soil

§  All High Dega

§  All Dega

§  All Weyna Dega

§  All Kolla

§  Moist Berha

o   Grassland Improvement 

§  Slope Range: All

§  Soil Range: All

§  Moist and Wet Dega

§  Moist and Wet Weyna Dega

§  Moist and Wet Kolla

·         CONSERVATION MEASURES ON FORESTLAND

o   Hillside Terrace 

§  Slope Range: 50 to 100%

§  Soil Range: On heavily degraded land

§  Moist High Dega

§  Dry and Moist Dega

§  Dry and Moist Weyna Dega

§  Dry and Wet Kolla

o   Microbasin 

§  Slope Range: All

§  Soil Range: All except highly degraded land

§  Moist High Dega

§  Dry and Moist Dega

§  Dry and Moist Weyna Dega

§  Dry and Wet Kolla

o   Tree Planting 

§  Slope Range: All

§  Soil Range: All except highly degraded land

§  All High Dega

§  All Dega

§  All Weyna Dega

§  All Kolla

§  Moist Berh

o   Trench 

§  Slope Range: All

§  Soil Range: All

§  Dry and Moist Dega

§  Dry and Moist Weyna Dega

§  Dry and Wet Kolla

·         CONSERVATION MEASURES COMMON TO ALL LAND USE TYPES

o   Area Closure 

§  Slope Range: All

§  Soil Range: All

§  All High Dega

§  All Dega

§  All Weyna Dega

§  All Kolla

§  Moist Berha

o   Checkdam 

§  Slope Range: All

§  Soil Range: Take care on deeply weathered rock or

§  loosely accumulated deposits

§  All High Dega

§  All Dega

§  All Weyna Dega

§  All Kolla

§  Moist Berha

o   Cutoff Drain

§  Slope Range: 3–50%

§  Soil Range: All

§  All High Dega

§  All Dega

§  All Weyna Dega

§  All Kolla

§  Moist Berha

o   Gully Rehabilitation

§  Slope Range: 0–30%

§  Soil Range: All, but take care on deeply weathered

§  soils or loosely accumulated deposits

§  All High Dega

§  All Dega

§  All Weyna Dega

§  All Kolla

§  Moist Berha

o   Revegetation 

§  Slope Range: All

§  Soil Range: All

§  All High Dega

§  All Dega

§  All Weyna Dega

§  All Kolla

§  Moist Berha

o   Water Harvesting

§  Slope Range: All (note specific limitation)

§  Soil Range: All

§  All High Dega

§  All Dega

§  All Weyna Dega

§  All Kolla

§  Moist Berha

o   Waterway 

§  Slope Range: 3–50%

§  Soil Range: All, but take care on deeply

§  weathered subsoils

§  All High Dega

§  Moist and Wet Dega

§  Moist and Wet Weyna Dega

§  Moist and Wet Kollla

§  Moist Berha