🌊 Watershed Management

Watershed

• The word “watershed” introduced in 1920 was used for the “water parting boundaries”. Watershed is that land area which drains or contributes runoff to a common outlet.
• Watershed is defined as a geohydrological unit draining to a common point by a system of drains. A watershed is an area of land and water bounded by a drainage divide within which the surface runoff collects and flows out of the watershed through a single outlet into a lager river or lake.
• Watershed technology is used in Rainfed areas.
• Catchment area is the water collecting area. “All the areas from which water flows out into a river or water pool”.

Watershed Management

• Watershed management implies an effective conservation of soil and water resources for sustainable production with minimum non-point resources (NPS) pollutant losses. It involves management of land surface and vegetation so as to conserve the soil and water for immediate and long term benefits to the farmers, community and society as a whole.

Main Aim of Watershed Construction

1. To harvest maximum total quantity of runoff water throughout the year for irrigation and drinking purposes.
2. To reduce the peak rate of runoff for minimizing soil erosion and sediment yield or to increase ground water recharge.

Objectives of watershed management

1. To control damaging runoff and degradation and thereby conservation of soil and water. (In situ conservation of soil moisture)
2. Increase gross cropped area, production and productivity.
3. To protect, conserve and improve the land of watershed for more efficient and sustained production.
4. To protect and enhance the water resource originating in the watershed.
5. To check soil erosion and to reduce the effect of sediment yield on the watershed.
6. To rehabilitate the deteriorating lands.
7. To moderate the floods peaks at downstream areas.
8. To increase infiltration of rainwater.
9. To improve and increase the production of timbers, fodder and wildlife resource.
10. To enhance the ground water recharge, wherever applicable.
11. Employment generation through industrial development dairy fishery production
12. Recreational facility

Impact of Watershed Development

• Increase in area under cultivation.
• Increase in the productivity of various crops.
• Significant increase in ground water recharge in watershed areas
• Increase in the net sown area and irrigated area in the watersheds.
• Increase in cropping intensity.
• Reduction in migration due to creation of employment opportunities in the watershed project areas (villages).
• Decrease in Soil Errosion.

Types of Watershed

Watershed is classified depending upon the size, drainage, shape and land use pattern.

1. Macro watershed: 1000 - 10,000 ha
2. Micro watershed: 100 - 1000 ha ^{UPPSC 2021}
3. Mini watershed: 10 - 100 ha
4. Mili watershed: 1 - 10 ha

Main Components of Watershed

1. Soil and water conservation
2. Water harvesting and water management
3. Alternate land use system

Steps in watershed management

• Watershed management involves determination of alternative land treatment measures for, which information about problems of land, soil, water and vegetation in the watershed is essential.
• In order to have a practical solution to above problem it is necessary to go through four phases for a full-scale watershed management.

Four phases of the programme

1. Recognition phase
2. Restoration phase
3. Protection phase
4. Improvement phase

Recognition Phase

• It involves following steps:
  • Recognition of the problem
  • Analysis of the cause of the problem and its effect
  • Development of alternative solutions of problem
• Necessary information is obtained from different surveys like soil survey, land capability survey, agronomic survey, forest, engineering and socio-economic survey, etc. This information serves as a basis for fixing and determining the watershed problems, priorities in land treatment measures, and causes and effects of problems on land and people.

Restoration Phase

• It includes two main steps:
  • Selection of best solution to problems identified
  • Application of the solution to the problems of the land As per the priorities, treatment applied initially to critical areas. After this proper measures like biological and engineering measures are applied to all types of lands.

Protection Phase

• This phase takes care of the general health of the watershed and ensures normal functioning.
• The protection is against all factors which may cause determined in watershed condition.

Improvement Phase

• This phase deals with overall improvement in the watershed and all land is covered. Attention is paid to agriculture and forest management and production, forage production and pasture management, socio economic conditions to achieve the objectives of watershed management.
• Health, family planning, improving cattle, poultry, etc. are taken depending upon intensity.

Water Resources Development Plan

• Water resource management plays a vital role in sustainable development of watershed which is possible only through the implementation of various water harvesting technique. The efficient way for sub-surface water storage, soil moisture conservation or ground water recharge technologies should be adopted properly under water resource development plan.
• The various measures adopted under soil and water harvesting is:
  • Vegetative barriers
  • Building of contour bunds along contours for erosion
  • Furrow/Ridges and Furrow ridge method of cultivation across the slope.
  • Irrigation water management through drip and sprinkler methods.
  • Planting of horticultural contour species on bunds.

Watershed management programmes in India

1. Drought Prone Area Programme (DPAP)
   • Year of start: 1970-71
   • Objectives: Area development programme through restoration of ecological balance and optimum utilization of land, water, livestock and human resources to mitigate the effect of drought.
2. Desert Development Programme (DDP)
   • Year of start: 1977-78

• Objectives: Mitigate the effect of drought in the desert area and restore ecological balance.

3. National Watershed Development Programme for Rainfed Agriculture (NWDPRA)
   • Year of start: 1986-87
   • Objectives: To conserve and utilize rain water from both arable and non-arable lands on watershed basis. To increase the productivity of crops and to increase the fuel, fodder and fruit resources through appropriate alternate land use system.
4. World Bank Assisted Integrated Watershed Development Programme
   • Project Year of start: 1990
   • Objectives: To arrest the problems of environmental degradation and promote sustainable increase in agriculture production and to enhance vegetative technology of soil and water conservation for rain water conservation and for increasing crop, forage, fuel wood and timber yield of the area.
5. Watershed Development Component of Pradhan Mantri Krishi Sinchai Yojana (WDC-PMKSY)
   • The Department of Land Resources, Ministry of Rural Development has been implementing an area development programme i.e. Integrated Watershed Management Programme (IWMP) w.e.f. 2009 principally for development of rainfed portions of net cultivated area and culturable wastelands.
   • The activities undertaken inter alia include ridge area treatment, drainage line treatment, soil and moisture conservation, rain water harvesting, nursery raising, afforestation, horticulture, pasture development, livelihoods for asset-less persons, etc.
   • Subsequent to approval of Pradhan Mantri Krishi Sinchayee Yojana (PMKSY), IWMP was subsumed as one of its components.
   • The Operational Guidelines of PMKSY were approved on 26.10.2015 as per which IWMP is implemented as Watershed Development Component of PMKSY (WDC-PMKSY).
   • The salient features of the Watershed Development component of the Pradhan Mantri Krishi Sinchayee Yojana (PMKSY):
     • Cluster Approach in selection and preparation of projects: Average size of project - about 5,000 ha.
     • Enhanced Cost Norms from Rs 6000 per ha to Rs 12,000/ha in plains; Rs 15,000/ ha in difficult/hilly areas.
     • Uniform Funding pattern of 90:10 between Centre & States.
     • Release of central assistance in three installments (20%, 50% & 30%) instead of five installments
     • Flexibility in the project period i.e. 4 to 7 years.
     • Scientific planning of the projects by using IT, remote sensing techniques, GIS facilities for planning and monitoring & evaluation.
     • Earmarking of project funds for OPR preparation (1%), Entry point activities (4%), Capacity building (5%), Monitoring (1%) and Evaluation (1%).
     • Introduction of new livelihood component with earmarking of project fund under Watershed Projects i.e. 9% of project fund for livelihoods for asset less people and 10% for production system & micro-enterprises.
     • Delegation of power of sanction of projects to States.
6. Neeranchal National Watershed Project
   • Neeranchal will lead to reducing surface runoff of rainwater, increasing recharge of ground water and better availability of water in rainfed areas resulting in incremental rainfed agriculture productivity, enhanced milk yield and increased cropping intensity through better convergence related programmes in project areas.
   • The project will be implemented by the Ministry of Rural Development.
   • The project will be implemented for a six-year period (2016-21).
   • During this period, it will support the Pradhan Mantri Krishi Sinchayi Yojana in hydrology and water management, agricultural production systems, capacity building and monitoring and evaluation.
   • The Neeranchal project was approved by the cabinet with Budget sharing of 50% by Govt and rest 50% by the World Bank.

Watershed Management Practices

A. In Terms of Purpose

1. To increase infiltration
2. To increase water holding capacity
3. To prevent soil erosion

B. Method and Accomplishment

1. Vegetative measures/Agronomical measures:

• (a) Strip cropping
• (b) Pasture cropping
• (c) Grass land farming
• (d) Wood lands

2. Engineering measures/Structural practices:

• (a) Contour bunding
• (b) Terracing
• (c) Construction of earthern embankment
• (d) Construction of check dam
• (e) Construction of farm ponds
• (f) Construction of diversion
• (g) Gully controlling structure
• (h) Rock dam
• (i) Establishment of permanent grass and vegetation
• (j) Providing vegetative and stone barriers

Rainwater Harvesting

• Rainwater harvesting means collection and storage of rainwater by some mechanism to make water available for future use.
• An appreciable amount of precipitation, which is generally lost as surface flow, can be harvested and stored for useful purposes like drinking and providing supplemental irrigation to the crops.

Some Important Points

• Watershed is also called as Hydrological unit.
• The most important approach in micro watershed is soil conservation, soil improvement and storage of run-off water.
• Silt distension tanks (water storage structure) will recharge ground water and ultimately used for protective irrigation.
• Insitu water harvesting is the potential life saving measure under moisture stress.
• Micro catchments are beneficial because:
  • (a) Increase moisture storage in deeper layer,
  • (b) Suitable for all soils,
  • (c) Specifically suitable for horticultural tree crops.

Water Budgeting

• A water budget is a water management tool used to estimate the amount of water a landscape will require. It can be calculated for a single irrigation event, on a weekly or monthly basis, or even annually.
• The water budget takes into account reference evapotranspiration data, plant type(s), purpose and functionality of the landscape, irrigated landscape area, irrigation efficiency, water quality, and rainfall.
• Since semi-arid regions depend on groundwater in the post monsoons, communities were capacitated to monitor their groundwater levels using a water level indicator. Bi-monthly data collected captures the groundwater fluctuation and is publicly displayed. Based on this information, crop plans are made (prior to the rabi sowing, taking care to secure sufficient water for livestock and domestic purposes in summer). Efficient irrigation methods (drips, sprinklers, micro irrigation systems) are being adopted.

In Watershed Management

• Crop water budgeting exercise is a community led process, where local communities come together to make an assessment of water resources in a given village.
• In this process, villagers basically explore answers to these three sets of questions:
  • What is the quantity of water available in the village?
  • What is the quantity of water that is used in the village, for different purposes?
  • What is the balance of water available in the village?
• Understanding the situation of the villagers, whether it is positive balance ("surplus") or negative balance (“deficit”).
• Discuss various options for conservation, use, management and regulation of water resources in the village.