Download - Targeting interventions to reduce catchment sedimentation sub watershed in the White Volta basin

A Partner of

Targeting interventions to reduce catchment sedimentation: The case of a sub-watershed in the

White Volta Basin

Kizito F., Obuobie, E., Venot J.P., Le Page C., and Daré W

Andes • Ganges • Limpopo • Mekong • Nile • Volta

Presentation outline1. Key message2. Background and Purpose3. Methodology4. Findings5. Lessons 6. Recommendations


Key message

- Study illustrates the relevance of distributed erosion models to target erosion control measures

- Illustrates the use of vegetative buffer strips to reduce erosion rates by 10-20%

- Importance of community involvement


Background and Purpose

- Study area lies in the White Volta Basin - Coverage of sub-basin is about 2,400

sq.km- Major issues relate to climate variability,

poor soil functions, and reduced storage capacity of reservoirs

- Intervention: landscape management to reduce erosion and sedimentation


Background

%

%

%

_ _

_

_

_

_

___

__ __ ___ _

__ __ ___ __

___ __ ___ __ ___ _ ___ ___ _ __ _ _ __ __ __ __ ___ __ _____

_

#*

#*

5

5

5

5

55

5

5

5

5Nangodi on Red Volta

Yarugu on White Volta

BANSI BAWKU

TILLI

BIDURI

BINABA

TIMONDE

KOSANABA

WIDENABA

NAFKULIGA

ZONGOYIRI

0°0'0"

0°0'0"

11°0'0"N 11°0'0"N

±0 7 14 21 283.5

Kilometers

V4 Watershed

5 V4 Communities

White Volta Basin Boundary

_ Small reservoirs

#* Flow Stations

Rivers


Methodology

Hydrological modeling

GEOSFM

Wet season Dry season

Participatory methods


Findings


Findings

19681970

19721974

19761978

19801982

19841986

19881990

19921994

19961998

20002002

20090.00

100.00

200.00

300.00

400.00

500.00

600.00 0

200

400

600

800

1000

1200

1400

1600

Rainfall Confidence band Observed Flow Simulated Flow

Disc

harg

e (m

3/s)

Rain

fall

(mm

)


Findings

Major contribution: Upstream catchments


Findings

- NE portion is most vulnerable- Highly linked to landscape

attributes


Findings

- With vegetative buffers in place- Erosion reduction by up to 15%


Recommendations

- Explore linkage with V1 on scaling out interventions

- Targeted interventions are context specific dependent on the biophysical characteristics as well as social dimensions

- Intervention need to consider associated environmental consequences, use of ecosystem based approaches would be appropriate