Introduction
Background
Methods and materials
Description of the study area
SWAT model input and data analysis
Digital elevation model (DEM)
Soil data
ID | Soil name | SWAT CODE | Area (km2) | Area (%) |
---|---|---|---|---|
1 | Calcic Vertisols | CALCICFLV | 105.421 | 11.53 |
2 | Eutric Leptosols | EUTRICLEPT | 1.175 | 0.13 |
3 | Eutric Vertisols | EUTRICFLV | 769.726 | 84.15 |
4 | Eutric Cambisols | EUTRICCAM | 38.378 | 4.20 |
Climatic data
A. Filling missing data
B. Consistency
C. Homogeneity test
D. Areal rainfall computation
Stream flow data
Land use land covers data
Model calibration and validation
Model performance evaluation
Result
Land use and land cover analysis
ID | Station | Data type | Latitude | Longitude |
---|---|---|---|---|
1 | Chacha | Precipitation only | 9.55 | 39.45 |
2 | Debrebirhan | Precipitation, temperature(Max, Min),wind speed, solar radiation, relative humidity | 9.633333 | 39.5 |
3 | Deneba | Precipitation only | 9.766667 | 39.2 |
Land use/LAND cover | Land use according to SWAT database | SWAT code |
---|---|---|
Agricultural land | Agriculture land to grown | AGRL |
Forest land | Forest mixed | FRSD |
Grass land | Range-grass | RNGE |
Urban | Less dense settlement | URBN |
Land use type | 1996 | 2006 | 2016 | 2006–1996 | 2016–2006 | 2016–1996 |
---|---|---|---|---|---|---|
Agriculture | 63.3 | 75.95 | 85.7 | 12.7 | 9.8 | 22.4 |
Grass land | 21.8 | 16.6 | 4.31 | − 5.2 | − 12.3 | − 17.5 |
Forest | 14.9 | 7.01 | 9.6 | − 7.9 | 2.6 | − 5.3 |
Urban | 0.01 | 0.42 | 0.44 | 0.4 | 0.0 | 0.4 |
Stream flow modeling
Sensitivity analysis
Parameter name | Parameter value range | p value | t stat | Calibrated value | Sensitivity rank |
---|---|---|---|---|---|
R__CN2.mgt | − 5%–25% | 0.0001 | − 11.22 | 6.25 | 1 |
R__SOL_K(..).sol | − 25%–25% | 0.0002 | 4.99 | 24.75 | 2 |
R__SOL_AWC(..).sol | − 25%–25% | 0.001 | 4.95 | 4.25 | 3 |
V__GW_DELAY.gw | 30–450 | 0.002 | − 3.56 | 74.10 | 4 |
R__REVAPMN.gw | 0–500 | 0.03 | 2.25 | 417.5 | 5 |
Flow calibration
Model validation
period | Mean Monthly stream flow(m3/s) | R2 | NSE | |
---|---|---|---|---|
Observed | Simulated | |||
Calibrated (1990–2002 | 10.0 | 12.4 | 0.83 | 0.81 |
Validated (2003–2009) | 12.1 | 13.9 | 0.87 | 0.86 |
Impact of LULC change on stream flow
Mean Monthly streamflow (m3/sce) | Mean monthly flow change | ||||
---|---|---|---|---|---|
LULC | 1996 | 2006 | 2016 | 2006–1996 | 2016–2006 |
Dry | 39.8 | 41.7 | 42.1 | 1.9 | 0.4 |
Wet | 604.1 | 632.1 | 648.3 | 27.9 | 16.2 |
Mean Monthly streamflow (m3/sce) | Mean monthly flow change | ||||||
---|---|---|---|---|---|---|---|
LULC map | 2006–1996 | 2016–2006 | |||||
1996 | 2006 | 2016 | m3/sce | % | m3/sce | % | |
211.0 | 224.4 | 229.8 | 13.4 | 6.0 | 5.4 | 2.3 |
parameter | LULC map | Change of SURQ(mm) | |||
---|---|---|---|---|---|
1996 | 2006 | 2016 | 1996 to 2006 | 2006 to 2016 | |
SURQ (mm) | 211.63 | 221.81 | 227.17 | 10.18 | 5.36 |