WATERSHED management defination objective
- 1. 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 geo- hydrological 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. WATERSHED
- 3. 1. an area or ridge of land that separates waters flowing to different rivers, basins, or seas. 2. A watershed, also known as a drainage basin, is an area of land where all water drains to a central point like a lake, river, or stream. watershed features i. Size – The watershed size varies from micro to very large. Accordingly, they have different characteristics. ii. Drainage Divide – Also called watershed boundary. It plays very significant role to divide the water flow from the area, i.e., whether the water is flowing towards or away from the area within the watershed.
- 4. iiii. Topography – It basically refers to the terrain of the land within watershed boundary. Terrain affects the trend of flow, e.g., if the area is steep then flow of water is very quick which may result into occurrence of severe soil erosion. On the other hand, if terrain is flat, then there is very little possibility of soil erosion occurrence. iv. Soil type – The soil is also considered as one of the very important features of watershed, because it affects the watershed behavior, significantly. For example – a belt of sandy, soil in watershed absorbs huge amount of rainwater from the rain event resulting into very low contribution for overland flow/runoff yield from there.
- 5. Classification of Watershed In general, the watershed classifications are based on the following parameters: i. The size ii. The drainage iii. The shape; and iv. The land use pattern. 1. Watershed Classification Based on Size: These are presented in
- 6. 2. Watershed Classification Based on Shape: Hydrologically, the shape of watershed is very important because it controls the time for the runoff to concentrate at the outlet, i.e., the time of concentration; and thus affecting the watershed’s hydrological behavior. The most common shapes are given as under: i. Fan shape:- The fan shape watersheds are normally in circular shape; ii. Fern shape:- fern shape watersheds are in elongated form. 3. Watershed Classification Based on Soil: These are mentioned as below: i. Red soil watershed; and ii. Black soil watershed.
- 7. 4. Watershed Classification Based on Slope of Land: Under this classification, the watersheds are classified as follows: i. Hilly watershed; and ii. Flat land watersheds. Hilly watershed Flat land watersheds 5. Watershed Classification Based on Climate: These are as below: i. Humid watershed; ii. Arid watersheds
- 8. Small is ecologically efficient as 10 dams with 1 hectare catchment will store more water than 1 dam of 10 hectare. There is a clear relationship between size of catchment and amount of runoff that can be captured. It shows that just increasing the size of the catchment from 1 ha to about 2 ha reduces the water collected per hectare by as much as 20 percent. Characteristics of watershed 1. Size: The soil maps, aerial photographs are used to determine the size of watersheds.
- 10. 3) Hydrologic soil-cover comlplex Combination of specific soil and specific cover is referred as soil-cover complex, the soils and vegetative covers of the watershed are classified, separately. Measure of this complex is used as one of the watershed parameter for estimating the runoff. a)Soils For hydrological analysis of watershed the hydrological properties of soil or the group of soil are essential factors . Normally the following four major soil group are recognized: •Group A: the soil having high infiltration •Group B: moderately infiltration •Group C: slow infiltration •Group D: Very slow infiltration b) Cover Any material can be used for covering the soil surface to protect the soil against rainfall. The vegetative material are commonly used to cover the soil. (Commonly used vegetative materials like fallow, row crops, legumes crops, Pasture or range, wood lands, permanent ungrazed grassland) 4) Geology and Soils: Rocks and their structures control the formation of a watershed itself their nature determines size, shape, physiography, drainage and ground water conditions and soil parameters Rock and soils together influence water storage, movement and infiltration
- 11. Watershed Management Watershed management is a term used to describe the process of implementing land use practices and water management practices to protect and improve the quality of the water and other natural resources within a watershed by managing the use of those land and water resources in a comprehensive manner.
- 12. Objectives of Watershed Management: Production of food, fodder, fuel. Pollution control Over exploitation of resources should be minimized Water storage, flood control, checking sedimentation. Wild life preservation Erosion control and prevention of soil, degradation and conservation of soil and water. Employment generation through industrial development dairy fishery production. Recharging of ground water to provide regular water supply for consumption and industry as well as irrigation. Recreational facility.
- 13. Principles of watershed management The main principles of watershed management based on resource conservation, resource generation and resource utilization, are 1. Utilizing the land according to its Capability. 2. Protecting productive top soil. 3. Reducing siltation hazards in storage tanks and reservoirs and lower fertile lands. 4. Maintaining adequate vegetation cover on soil surface throughout the year. 5. In-situ conservation of rain water. 6. Safe diversion of excess water to storage points through vegetative waterways. 7. Stabilisation of gullies by providing checks at specified intervals and thereby increasing ground water recharge. 8. Increasing cropping intensity and land equivalent ratio through intercropping and sequence cropping.
- 14. 9. Safe utilization of marginal lands through alternate land use systems with agriculture - horticulture - forestry - pasture systems with varied options and combinations. 10. Water harvesting for supplemental and off season irrigation. 11. Maximizing agricultural productivity at convenient locations for unit area per unit time and per unit of water. 12. Ensuring sustainability of the eco-system befitting the man- animal- plant water complex. 13. Maximizing the combined income from the inter related and dynamic crop-livestock- tree-labour complex over years. 14. Stabilizing total income and to reduce the risks during aberrant weather situations. 15. Improving infrastructural facilities with regard to storage, transportation and marketing of the agricultural produce. 16. Setting up of small scale agro-industries; and 17. Improving the socio-economic status of the farmers.
- 15. FACTORS AFFECTING WATERSHED MANAGEMENT a) Watershed characters i) Size and shape ii) Topography iii) Soils b) Climatic characteristic i) Precipitation ii) Amount and intensity of rainfall c) Watershed operation d) Land use pattern i) Vegetative cover ii) Density e) Social status of inhabitants f) Water resource and their capabilities
- 16. Components of Watershed Management Components of Watershed Management The three main components in watershed management 1. Land Management 2. Water Management 3. Biomass management 1. Land or soil Management Land characteristics like terrain, slope, formation, moisture, infiltration rate and soil capability are the major determinants of land management activities in a watershed.
- 17. Soil conservation techniques In broad sense the land management intervention including the following activity a) Vegetative measures:- Primary land management mesures Contour farming Strip cropping Vegetative bunding Grassland management Mulching Agroforestry b) Structural measures:- Bunding Terracing Check dams Gully contol Farm Pond c) Production measures:- Mixed cropping Strip cropping Cover cropping Crop rotation Bunding Contour farming Strip cropping Mulching Terracing Check dams
- 18. Cultivation of shrubs and herbs Contour cultivation Conservation tillage Land levelling d) Protection measures Control structure Gully plugging structure Runoff collection structure Contour farming/Bunds Gully control Reclamation of alkaline soil Green carpeting 2. Water Management The broad interventions for water management are listed below; Rain Water Harvesting Ground Water Recharge Maintenance of Water Balance Preventing Water Pollution
- 19. Rain Water Harvesting Rainwater harvesting forms the major component of water management. The rainwater collected can be recharged into the ground. Roof top water harvesting, diversion of perennial springs and streams in to storage structures, farm ponds etc. are the methods widely used for rainwater harvesting.
- 20. Types of Run off harvesting 1.Runoff Farming 2.Water Spreading 3.Microcatchments 4.Dug wells 5.Tanks 6.Percolation tanks 7.Nala bunds 8.Stop dams 9.Farm ponds 3. Biomass Management Major intervention areas for biomass management are indicated below; Eco-preservation Biomass Regeneration Forest Management & Conservation Plant and other vegetation Protection Increased Productivity of Animals
- 21. Advantages of watershed approach Environmental friendly Saves time and money Greater people’s participation 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. Programme: a. Recognition phase. b. Restoration phase. c. Protection phase. d. Improvement phase.
- 22. (i) Recognition Phase: It involves following steps (a)Recognition of the problem (b) Analysis of the cause of the problem and its effect. (C) Development of alternative solutions of problem. (ii) Restoration Phase: It includes two main steps. (a) Selection of best solution to problems identified (b) Application of the solution to the problems of the land (iii) 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. (iv) 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.
- 23. What is cropping System: It represents cropping patterns used on a farm and their interaction with farm resources, other farm interprises and available technology which determine their make up. Cropping pattern means the proportion of area under various crops at a point of time in a unit area. It indicates the yearly sequence and spatial arrangement of crops and fallow in an area. Crop sequence and crop rotation are generally used synonymously. Crop rotation refers to recurrent succession of crops on the same piece of land either in a year or over a longer period of time. Component crops are so chosen that soil health is not impaired. Cropping systems for watershed areas
- 26. Types of cropping systems • Depending on the resources and technology available, different types of cropping systems are adopted on farms. Monocropping • Monocropping or monoculture refers to growing of only one crop on a piece of land year after year. • Under rainfed condition ground nut or cotton or sorghum are grown year after year due to limitation of rainfall. • Mono cropping is practiced under normal and below normal rainfall conditions by adopting improved methods of moisture conservation practices and short and medium duration varieties of the crops, either in kharif or Rabi season. Monocropping in normal and below normal rainfall years. • Kharif crops – fallow • Fallow- rabi crops (on conserved moisture)
- 27. Multiple cropping • Growing two or more crops on the same piece of land in one calendar year is known as multiple cropping. • It is the intensification of cropping in time and space dimension • It includes double cropping, intercropping , mixed cropping and sequence cropping. • Use of seeds of drought resistant, early, quick growing and high yielding varieties of the crops with improved agronomic management and cropping system depending upon the rainfall pattern bring about definite improvement in dryland crop yields. • Pearlmillet, mungbean, black gram, cowpea and clusterbean during rainy season • chickpea, mustard and taramira during Rabi season were identified to be the promising crops for the dryland areas of the region.
- 28. Double cropping in above normal rainfall years: • Pearlmillet- chickpea, Mungbean-Mustard, Cowpea-mustard, Pearlmillet + Cowpea Mustard/Chickpea • Intercropping - Pearlmillet + Mungbean, Pearlmillet + clusterbean • Mustard (RH-30, Varuna, RH-819 and Lakshmi) and gram (H- 208 and C-235) were identified most suitable crops for planting on well conserved soil moisture.