Dr. Vivek KumarDr. Vivek Kumar

ST. VINCENT PALLOTTI ST. VINCENT PALLOTTI COLLEGE OF ENGG. AND COLLEGE OF ENGG. AND

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Watershed:

Definition:“Watershed can be defined as a unit of area covers all the land which contributes runoff to a common point or outlet and surrounded by a ridge line”.

Deterioration of watershed takes place due to faulty and bad management through the activity of man and his animals.

Causes of watershed Deterioration:

These activities are:Faulty agriculture, forestry and pasture (Grass land) management leading to degradation of land.

Unscientific mining and quarrying.Faulty road alignment and construction.

IndustrializationForest Fires Apathy (less interest) of the people.

Results of watershed Deterioration:

Less production from agriculture, forests, grass lands etc.

Erosion increases and decreases biomass production

Rapid siltation of reservoirs, lakes and river beds.

Less storage of water and lowering of water table.

Poverty as a result of less food production.

WATERSHED DEVELOPMENTPossible range of treatment measures

Contour bunding Contour trenching Contour stone walls Bench terraces Land levelling Summer ploughing

Agro forestry with suitable species

Vegetative barriers Check dams (Temporary and Permanent)

Retaining walls Farm ponds and Percolation ponds

Renovation of existing water bodies and inlet channels

COMPONENTS OF WATERSHED DEVELOPMENT:  

• Human Resource Development (Community Development) • Soil and Land Management• Water Management • Crop Management• Afforestation • Pasture/Fodder Development • Livestock Management • Rural Energy Management • Farm and non-farm value addition activities

All these components are interdependent and interactive.

DEVELOPED WATERSHED

Methods for hill slopesCONTOUR TRENCHES AND STONE WALLS

BENCH TERRACING

CONTOUR TRENCHES AND STONE WALLS

Suitable erosion control in hills

Adopted for hill slopes >20%

Continuous or interrupted

BENCH TERRACING

It helps to bring sloping land into different level strips to enable cultivation.

It consists of construction of step like fields along contours by half cutting and half filling.

Original slope is converted into level fields. The vertical and horizontal intervals are decided based land slope.

Methods for agricultural landCheck damPercolation pondMicro catchmentsContour bundBroad beds and furrowsGully plugsTree plantationSummer ploughing Agro forestry Vegetative barriersFarm ponds

Check dam

Check Dam

A low weir normally constructed across the gullies

Constructed on small streams and long gullies formed by erosive activity of flood water

It cuts the velocity and reduces erosive activity

The stored water improves soil moisture of the adjoining area and allows percolation to recharge the aquifers

Height depends on the bank height, varies from a 1 m to 3 m and length varies from less than 3m to 10m

 Percolation pond

To improve the ground water recharge.

Shallow depression created at lower portions in a natural or diverted stream course

Located in soils of permeable nature

Adaptable where 20-30 ground water wells for irrigation exist with in the zone of influence about 800 X 900 m

Micro catchments

To conserve insitu moisture and reduce soil loss

Circular basin of one meter dia for level lands depending upon infiltration and rainfall

Ditches of size 5m x 5m with trees planted centre

Saucer basins / semi circular bunds with 2m diameter to a height of 15-20cm across the slope

Broad beds and furrows

To control erosion and to conserve soil moisture in the soil during rainy days  

The broad bed and furrow system is laid within the field boundaries.

Conserves soil moisture in dry land.

Controls soil erosion.Acts as a drainage channel during heavy rainy days.

Contour bund

To intercept the runoff flowing down the slope by an embankment.

It helps to control runoff velocity.

It can be adopted in light and medium textured soils.

It can be laid up to 6% slopes. It helps to retain moisture in the field.

Gully plugs

Gully plug is one of the simple method of soil and water conservation. It plays an important role in soil and water conservation.

Gullies are formed due to erosion of top soil by the flow of rain water. In course of time, a gully assumes a big shape and erosion goes on increasing. To prevent erosion, barriers or plugs of different types of material are put across the gully, at certain intervals.

Tree plantationInstead of uneconomical agriculture, farmers can grow grass in this hilly area and can use that as a fodder for cattle.

Farmers can go for dairy development if good quantity and quality of grass is available.

For soil and water conservation this activity will help. Plantation on common land will satisfy basic need of fuel wood.

Cheapest method for soil and water conservation

Summer ploughing 

Main objective of field preparation is to control weeds

Facilitate easy sowing and to establish good seed soil contact

For easy absorption of moisture

To provide sufficient aeration To improve water holding capacity

Agro forestry Agroforestry is an integrated approach of using the interactive benefits from combining trees and shrubs with crops and/or livestock.

It combines agricultural and forestry technologies to create more diverse, productive, profitable, healthy and sustainable land-use systems.

Vegetative barriers

Vegetative barriers are also an effective inter-terrace land treatment in place of earthen barriers.

Farm ponds 

Roof top rainwater harvestingTo recharge the wells (open and tube wells) particularly abandoned wells by a runoff collection system.

Direct on-use of collected water if storage facility is available.

 RECHARGE TUBE WELL

To directly feed depleted aquifers to fresh water from ground surface so that the recharge is fast without any evaporation loss

Depth of recharge tube well depends on the present depth of bore wells in the area

Thank you