Water is most essential for all living beings: bacteria, plants, animals and humans. Water is an essential component even for organic and inorganic chemical reactions in the nature. We know life originated in water and in and through water only all forms of life have to survive, develop and complete their life cycle. Unfortunately humans are the ones who create water shortage and hence it is their responsibility to preserve water on this globe for the benefit of all living beings in it. Hence World Water Day is held every year on 22 March to focus every one’s attention on the importance of sustainable management of freshwater resources. Each year, World Water Day highlights a specific aspect of freshwater as a theme. In 2015, World Water Day had the theme was "Water and Sustainable Development". In 2016, the theme is "Water and Jobs”. Soil and water conservation implemented in a systematic and sustained way has the greatest potential to generate millions and millions of man days of employment in all the water scarcity and poverty stricken countries in the world. If implemented well it will be a huge long term investment capable of generating long term returns of accountable and unaccountable nature and magnitude.
Revisiting watershed management programmes in all the hilly and mountainous regions which are the actual catchment areas of the river-systems of any country is the first step any country should take both for solving the water scarcity and for generating productive employment. Globally the forests in the hilly and mountainous regions of most of the countries have been wiped away completely. As a result all the springs and streams that originated at the foot hills and mid-mountain ranges have dried up causing all rivers and natural inland water bodies to dry up causing the present water scarcity in most of the countries of the world. All the hilly and mountainous areas of most of the countries in the world should be covered with perennial forest cover which facilitates the sinking and socking of whatever rain and other forms of precipitation, deep into the soil and which will be released slowly to maintain the numerous springs and streams active throughout the year. As long as these springs and streams are active the rivers will be active with perennial flow of water; the water table in the plains will come up and remain stable; all the other inland water sources like wells, ponds, lakes, marshy lands, mangroves, low lying and waterlogged areas will be recharged with water. The ancient sustainable balance between the flow of water on the land area to the sea and the rain cloud movement from the sea to the mountainous regions and to the plains have to be restored to a sustainable water cycle in the nature. That is the only way to solve the global water scarcity problem at a sustainable and equitable manner and phase.
The rainfall pattern all over the world is changing and becoming more and more erratic. A perennial forest cover on mountains and hilly ranges above 33.3% slope (1:3 ratio of vertical to horizontal) is the first and perhaps is the only way to ensure increased and steady precipitation and its percolation deep into the mountain forest humus soil which will behave like a sponge socking in billions and billions of cubic metres of rain water which when percolated deeper and deeper will give rise to numerous mountain-springs from many topographical depressions, folds and pockets at the mid and foothills of mountain ranges. These springs combine together to form streams and the streams joined together to form rivers which join the sea or some inland water bodies. On the same vast and sprawling mountain ranges themselves, wherever possible, excess water from the springs and streams could be diverted into natural or artificially created storages of any size or shape. Similarly, wherever possible check dames and anicuts can be constructed in the streams to impound as much water as possible in situ or to divert water into the folds, depressions and valleys of mountain ranges where natural or artificial storages can be created.
Creating artificial lakes, dams or reservoirs of any size and shape in the mountain ranges is the best way of creating friendly environment for all the wild flora and fauna many of which are on the verge of extinction. Similar to Blue Mountains ranges in Australia suitable mountain ranges can be planned for eco-tourism or wild animal sanctuaries with strict monitoring. The natural status of this area should never be disturbed by humans for cutting timber trees or for collecting minor forest products or by domestic animals. If at all any timber tree is to be cut as an exception it should be accomplished only by employing cut-and-lift technology and never by employing cut and drag down through the forest method, as have been the practice so far. At present in most of the countries all the slopes above 33.3 per cent in the mountain ranges are devoid of perennial vegetation. UN and other international law enforcing bodies should make it mandatory for all the countries to reforest totally all the slopes above 33.3% with perennial forest cover in which no human or domestic animal activity should be allowed. Within 5-10 years every country should transform this slope range into perennial forest cover. Without compulsion there is no proper completion of anything in this world. Thus the World Water Day 2016 motto of “Water and Jobs” will become beneficial to millions of jobless poor people all over the world.
For the next lower range of slopes between 20 to 33.3 per cent the percolation of rain water can be facilitated by an integrated watershed management approach which consists mainly of components of soil and water conservation techniques. There are many soil and water conservation techniques and usually a combination of them could be employed to conserve soil and water in areas between 20 to 33.3 per cent slope. Prominent among them are the perennial plantation of local forestry trees and semi-wild fruit trees like tamarind, goose burry or other locally available wild or domesticated trees which have a life more than 40 to 50 years, combined with contour terracing and trenching along with small or big and longishly constructed water reservoirs along the contour lines to store the runoff and drained water. Planted forestry in the 20 to 33.3 per cent slope areas also have great potential for generating employment opportunities for millions of people.
The next range of slope between 10 to 20% could be covered with animal grazing farms, orchards and plantation crops interspaced with vegetable and flower cultivation which will have huge potential for employment generation through production, processing and marketing (PPM) products like fruits, vegetables, flowers and yields from all the plantation crops. Contour narrow terracing and drainages for water collection into contour level constructed longish trenches or tanks will the basic structures of the watershed management in this range of slope.
The next slope range, which requires treatment with watershed management techniques are areas within 5 to 10 per cent slope range. The treatments in this slope range consists mainly of contour terracing with properly laid out drainage channels ending in small or big water storages constructed under proper estimation and implementation. These areas can be cultivated with seasonal or perennial crops of cereals, pulses and vegetables, fruits, medicinal and aromatic plants, fibre and flower crops etc. again on a production, processing and marketing (PPM model) which has tremendous seasonal and perennial employment opportunities for millions of people.
The last range of slope form 0 to 5 per cent requires no heavy input of watershed management. The area may under seasonally cultivated crops or waste land or any land beset with problems like saline and alkali soils etc. Besides terracing and leveling there should be storage facilities for all excess water in the area.
The main principle of watershed management is that after implementation not a drop of rain-run-of-water should go out of the watershed nor a grain of soil should go out of the watershed area. Though this may look impossible what is meat is the importance implementing the watershed with that aim in view.
Along with the above mentioned slope treatment the following are also essential for the preservation of water bodies on the surface of the earth.
That proper implementation of watershed management can generate jobs for millions has been proved by the Indian experience which started at the rudimentary level in the Ahmednagar district in Maharastra in 1960’s by a German Jesuit missionary Fr. Herman Bakher (the undeclared father of watershed movement in India, because he had no political clout or godfather) who implemented soil and water conservation programmes both for augmenting water table as well as to generate employment for poverty stricken people in the drought hit areas of the same district. Helped by some sugar mill owners he facilitated construction of many barrages, check dams, anicuts, nalla bunds, gully plugs, contour trenches, contour bunds, percolation tanks which are the main components of any actual water conservation programme. They generated large number of immediate and proximate employment opportunities. Simultaneously there was a centrally sponsored scheme of “Soil Conservation Work in the catchments of River Valley Project (RVP)” launched in 1962-63. Only it was not implemented properly and sustainably as is the case with most of the development works in our country.
Later with the implementation of a large scale soil and water conservation programme by AFPRO led team in a huge contiguous area at Adgaon, in Maharastra, the concept of watershed development programme struck root in Indian soil. Maharashtra, a pioneer state in watershed development programme, has already reasonably conserved, regenerated and judiciously managed its water resources, over 12.6 million hectares of the state's 24.1 million hectares having 43,000 micro-watersheds. Hence this article advocates a revisiting of the almost dying watershed development programme of last century in our country to eradicate the water scarcity problem and to create millions of job opportunities.
Watershed management is not only a practice but also a philosophy based on socio-eonomic and political justice. It is an environmentally sound and ideal approach for a community based participatory development action. Various possible concepts and perspectives on watershed management are sketched in this article with the intention of generating a critical thinking among those who are involved in watershed development. But ultimately all water-shed management practices should lead to the development with justice and equity.
The main characteristics by which we can I identify a watershed area are: mouth, divide, upstream, sub-drainages, water cycle and organic matter cycle. The first four are visible on the watershed while the last two are invisible.
The term mouth here refers to the point of drainage towards which water is drained from every point in watershed through a single or numerous sub-drainages. Topographically, mouth will always be the lowest point of watershed. I The point of drainage or mouth is fixed on a drainage (rivers, streams or channels) according to the convenience and the demarcation of watershed through a divide begins on the one side of the mouth and ends on the other side.
The boundary line of a watershed is called divide. The term divide is used because the boundary is a dividing line between two watersheds. It is an imaginary line on the top of the hills or uplands which are considered the surrounding ridges of a watershed. Hence it is also called a ridge line.
Upstream refers to the area that lies above the mouth and extends up to the divide. This is the actual watershed area that receives or catches rain water and drains towards the mouth. Therefore, this area is also called catchment area. It should be kept in mind that the terms upstream and catchment area have more or less same meaning as watershed. The whole watershed area, however, ultimately slopes towards the mouth in a very intricate and labyrinthine way through numerous sub-drainages.
A watershed consists of numerous sub-drainages such as small rivers, streams, channels, gullies and rills which drain' water towards the mouth. The number of drainages in a watershed depends on the size of the watershed. Small drainages become tributaries to the big drainages and big ones to still bigger drainages till all join together into the main drainage forming a design on the watershed like that of a profusely branched tree. A sketch of a watershed with all its drainages look like the veins in a leaf. All these drainages small and big together maintain the water cycle on the watershed.
Watershed is a system. A system means a complex unit having various interrelated components which have their own functions within the system. They are so complex that each component and its functions can be considered separately depending on the aspect or component one wants to emphasize. We can view watershed as a (1) geographical system, (2) physical system, (3) inorganic system, (4) water ! cycle system, (5) organic matter system, (6) organic matter : cycle system, (7) combination of water and organic matter cycle, (8) medium of cycles, (9) ecosystem, (10) flora centered system, (11) fauna-centered system, (12) homo centered system, (13) economic system, (14) social system, (15) political system, and (16) integrated economic and socio-political system.
The different concepts of watershed are developed based on these aspects. However, these aspects cannot be separated from one another. But for greater clarity in understanding they can be studied separately. The successive stages in the evolutionary developmental process in which economic self-sufficiency form the basis of social stability and a stable society gives rise to a stable political system. Socio-ethenic and cultural factors consolidate or disintegrate a political system. However, the economic self-sufficiency is the foundation for a vibrant social system and stable political system. However, an economic-socio-political system should have a scientific and practical basis. Economic stability of watershed depends on the sound management of the natural resources of a watershed. Hence watershed needs to be studied from its various resource components enumerated earlier. One can look at this list from a progressive and evolutionary-chain-reaction point of view or from the dependency chain.
Watershed at the first sight is a definite geographical area which receives drained out rain water. Watershed is a big surface drainage system. The magnitude of the watershed is determined by the elevation of point of drainage: lower the drainage point, the greater will be the area of watershed and the higher the elevation of drainage point, the smal1er will be the watershed area. Obviously drainage point at sea level will comprise maximum watershed area. Depending on the area of watershed it may be classified into micro, mini, medi, macro and mega watersheds. A micro watershed is less than 100 ha, whereas the macro watershed may be thousands of hectares.
The total area of watershed may be consisted of various topographical features such as lakes, tanks, marshes, rivers, streams, plain lands, undulated land, hills, mountains, rocks, cultivated land, fallow land, grazing land, degraded land, uncultivable land, forests and residential areas.
In the area approach topographical features form the major basis of planning of a watershed. Generally, topography of watershed varies from perfectly leveled land to 90 degree or 100% slopes. Depending on the percentage of area under a specific topographical designation, we may call an area hilly undulated, highly, medium or moderately sloppy, level able or naturally leveled land. Hence the watershed management practices will vary with degree and nature of slopes of various topographical features in the same watershed.
The geographical approach is necessary in preserving a watershed from degradation or to restore a degraded one. This approach may be adopted even to watersheds uninhabited by people. The main purpose of the watershed management will be to conserve the soil which result in the conservation of water and the enhancement of the regeneration of the vegetative cover. This approach is specifically useful to restore degraded uninhabited lands and deserting or desert areas.
A watershed has not only an area but it has other dimensions such as height and depth with reference to the surface. It has a space or air volume vertically above the watershed area. Similarly, it has a depth dimension comprising of the earth volume vertically below the watershed area.
The sky is the limit of the air volume above the watershed. The air volume or space receives moisture and retains it in the form of relative humidity. Relative humidity varies with temperature and pressure. Higher the temperature and pressure greater will be vapor content in the air. The rainfall in a place is influenced by the relative humidity, pressure and temperature of the air volume above it. The movement of air over the water changes constantly. The speed of the movement may vary from zero to several hundred kilometers per hour.
Temperature influences the watershed. A temperature varying between 15 to 35 degree C will be optimum range for watershed. Above or below this temperature plays a negative effect on the plants and animals in the watershed.
Air volume consisting of 79% nitrogen, 20% oxygen, 0.4% carbon dioxide and other gases (0.6%) is the optimum composition for a watershed. Any change in this composition can affect the watershed directly or indirectly. In many areas air pollution has become a major concern.
In the absolute sense the center of the earth is the limit of the depth of any watershed. However from practical point of view the water table or up to bed rock is considered as the depth of watershed. The volume of earth consists of minerals in the form of rocks and soil, moisture, hibernating animals (frogs, scorpions, snakes, lizards) plant roots and micro-organisms. The parent material of rocks and soil will have bearing on the watershed. Accordingly, one finds too much calcium, mica, iron, phosphorus, sulphur, manganese, sodium etc. more or less in the soil.
The soil is the actual crust of the earth and varies from few centimeters to a meter or two in depth. The main feature of this soil is that it contains organic matter in the form of humus or living organisms. The organisms may be micro as well as macro. The top soil contains more organic matter while the bottom soilless.
Rocks, stones, gravels, coarse sand, fine sand, silt and clay are the mineral matters in the macro form. At the elemental form, practically all the known elements are present in the soil. Soil is like a sponge and there are air spaces between soil particles. These are called pore spaces which may be bigger (macro pores) or small (micro pores). Strictly speaking pore space is the total surface area of all the soil particles. These pore spaces harbor moisture, humus and micro organisms. The soil depends on the texture and structure of the soil particles. The texture of the soil refers to the size of the soil particles which may be rocks, stones, gravel, coarse sand, fine sand, salt or clay. The structure of the soil refers to the arrangement of the soil particles. Water table is the level of water below the surface of the earth. The water table in a watershed may be very low or very high or fluctuate between these two according to season. It is measured vertically below the surface of the earth.
The present, level, movement and the quantity of water in the soil depends on the various factors such as soil particle size, climate, seasons, level of water table and rainfall. The soil in a watershed receives water from the air volume above it though there may be underground sources from adjacent watersheds.
Physically watershed can be defined as a combined volume of air and soil which receives water and drains out through a common drainage.
The management practices of a watershed should be adopted according to the humidity, temperature, air movement, air composition, soil depth, parent material, texture and structure of soil paI1icles, organic matter content, pore space, and water table.
Thus, in an area with high humidity and rainfall watershed management will mainly consists in conservation of soil and drainage of excess of water without damage to the watershed. For this, properly designed and laid out drainages are necessary. In a dry and arid area the emphasis will be on moisture conservation. More of mechanical and biological measures are resorted to this. Areas with high wind velocity, soil loss through wind has to be minimized. For this windbreaks and vegetative covers are established. In an area where the sun- shine is too hot, the key aspect in watershed management will be to provide vegetative cover to the lanc.1. If the soil is too shallow (less than one feet deep) the primary concern in the watershed management is to increase depth of the soil by repeated ploughings and harrowings. In sandy and sandy loam soil watershed management will be focused towards incorporation of the organic matter into the soil. If it is clay soil, sand and organic materials may be added to make it loamy. In area where soil particles are gravelly, addition of silt or clay and organic matter should be emphasized. In places where the water table is high, soil drainage becomes the key water management practice.
Watershed is a complex of chemical elements and their reactions. The elements are present in the watershed volume in solid, liquid and gaseous forms. These chemical elements, in the presence of each other, and under the influence of physical factors such as moisture, pressure, heat and light are in constant changes (different chemical reactions) are taking place in different forms (solid, liquid and gases). Depending on those various factors cel1ain chemical reactions may be favoured more than the others and consequently the chemical nature of the soil will be affected by them. For example under highly hot climate watershed areas having high water table can encourage high rate of evaporation leaving the salt on the surface of the soil. Depending on the type of salts the soil may turn out to be saline, alkaline or sodic. But if the rainfall is high and leaching rate is higher the soil becomes acidic. The anion and cation exchange capacity and the pH of the soil depends on the various types of inorganic com- pounds present in the soil.
Innumerable inorganic reactions are constantly taking place in the watershed volume. Hence watershed can be de- fined as a volume of inorganic materials which receives and drains out water through a common drainage.
Watershed management should take into consideration the chemical nature of mineral material of the soil. Whether acidic, alkaline, sodic, calcareousness or saline. In areas with high acidic soil, the watershed management practices should focus on besides other things, correction of acidic soils. Similarly, in areas of saline or alkaline soils corrective measures are introduced along with other watershed management practices. In the same way calcarious and gypsiferous soils are also treated with corrective measures in the watershed management system.
A watershed receives rain water and drains out and again receives and again drains it out. Such a process in the water- shed is called water cycle. In water cycle, water moves from ocean and other water bodies into air volume where it condenses to form rain which moves through and over the surface of the earth volume. The frequency of water cycle through the soil volume of watershed varies from continuous to a very short duration of less than an hour. It is through the process of water cycle that water is made available to every non- living and living things. But in order to make water available sufficiently to every thing all the time, a watershed should have a continuous water cycle irrespective of the frequency of the rainfall. The aim of the watershed management is to make the process of drainage slow enough to maintain the continuity of water cycle and establish a balance between the quantity of water received and drained during any given period of time. In other words the period of drainage of certain quantity of water received is lengthened to such an extent that it overlaps the period of reception of the same quantity of water into the watershed. The main source of water in watershed is rain or precipitation. However, water may be received both by the rain as well as from underground sources such as springs located adjacent to watersheds.
The inorganic reactions in the watershed are only a basis for much more complex actions and reactions at the organic level. In fact, the inorganic actions and reactions are part of the organic chemical reactions. Inorganic reactions with water is the beginning of organic reactions. Inorganic reactions can take place without water, whereas all organic reactions essentially require water. Water, thus form a necessary link between organic and inorganic reactions. Through these organic reactions chemical substances such as carbohydrates, proteins, vitamins, enzymes and hormones are produced. The most common and basic organic reaction in the nature is photosynthesis.
Watershed is not only a eco-geographical but also a socio-economic and political unit. People in this unit depend on it primarily for their existence and secondarily for their development with social justice and equity. In a watershed development approach, both these aspects should be taken into consideration. Existence without development is meaningless and development without existence is impossible. The ultimate aim of watershed management is development with justice. To attain such an aim we need to have an integrated approach in the watershed development.
Dr. K.T. Chandy
(Agronomist & Retired Professor
Environment and Natural Resource Management
Xavier Institute of Management, Bhubaneswar)