Article by V. Takalkar

CONTINUOUS CONTOUR TRENCHING TOOL FOR WATERSHED MANAGEMENT PROGRAMME

ABSTRACT

Watershed management is the need of the hour not only for soil conservation and ground water conservation. It also has impact on national economy and solutions for employment problem. In drought prone area, there are two critical factors Water and Soil In such areas main objective is covered with not only retention of soil in it's own place but also every drop of water, which infiltrates into the subsoil instead of flowing at surface (run off) causing soil erosion with evaporation. It recharges downstream water source e.g. nalla, dug wells, tube wells, etc. This CCT method reduces soil erosion to minimum, and the plant growth on such trenches is very promising with 90% to 95% survival. This method can be adopted in low rainfall area to high rainfall area and from flat area to hilly area with 65% steep slopes. This method is suitable for plantations of all species. It is easy and simple for laborers and involves comparatively less record keeping. There are drawbacks of this method. It is very tedious and laborious for alignment. It is time consuming to fulfill requirement of accuracy, skilled lab ours and instrument like contour marker are used. There is potential danger of water flowing along their upper edge in case the trench breaks. The economics of this CCT method is very interesting. One-milliliter rainfall in that area 500 milliliter and considering 50% evaporation losses, 2.5 million liters of water is infiltrated in subsoil to recharge ground water sources. Now a days in hilly areas, considering capacity of tanker 10,000 liter and cost of one trip from water source to needy area is Rs.500/- per trip average CCT works supply works supply 250 tanker/ hectare/year worth Rs.1.25,000/-. The expenditure for one hectare is approximately Rs.8,000/- in four years. so that benefit cost ration comes 8.33 from indirect benefits for one year only. The production of grass in one hectare is approximately 2 to 3 MT/hectare costing Rs.1000/- MT and thinning operation gives firewood and other products of wor5th cost approximately Rs.6400/- hectare in few years. In Henagar district of Maharashtra State (India) within four years. 17,831 hectares forest area us covered with this CCT method. The length of CCT is 22700km. The number of plant actually planted in the above mentioned area is 187.56 lakhs with average survival rate 94.25%. The average rainfall in Ahmednagar district is 500 mm. The approximate quantity of water conservations is 89.155 million cubic meters. Considering 50% evaporation and other losses, 44. 58 million cubic meters is infiltrated into the soil strata.

METHODOLOGY ASSUMPTION

For the watershed area with soil cover more than 30 cm to be treated, average length of 1200m CCT per hectare gives good results. Similarly for Soil cover in between 10 cm to 30 cm, average length of CCT per hectare is 1060 meter and for the are with soil cover less than 10 cm, feasible average length of CCT is 200 meter (assumed) per he.

COLLECTION OF DATA

After Selection of area where a forestation activity is to be carried out, first of all, detailed inspection of the total area is necessary for collection of data about.

• Available depth of soil cover

• Width and length of the streams in selected area

• Area and (definite) boundary marking

• Ground levels at bottom and top of the hills.

• Horizontal distance between bottom and top of the hill.

• Rain fall

• Depth and of level water column in the open wells.

• Length of CCT

• No of plants

THEORY

• From the collected data and map of the area, total work to be carried out can be assessed. Similarly possible minimum length of CCT can be worked out.

• From that data, average length of the trench can be calculated.

• Number of CCT line is calculated by using the relation. No of CCT line = Total work to be done / average length of CCT

• Height difference between top and bottom of the hill is calculated by using the collected data.

• Contour interval can be calculated by using the relation, contour interval = Total height difference/ No. of CCT lines.

INSTRUMENTS

• CONTOUR MARKER
  
  Counter marker consists of two staff members of 1 meter 1.50 meter height with piezometric transparent tube of 12 meter length to show the level difference between two points. Every staff member consists of scale of 1 meter. Each centimeter of scale is divided into four parts with accuracy of 0.25 cm. This instrument is used for finding out contour
  interval as well as to lay out the contour.
   

• CENTERLINE MARKER
  
  Centerline marker is simple instrument having two edges about 35cm apart with handle at center. Centerline of CCT is marked with the help of centerline marker.
   

• SPA-CEMENT MARKER
  
  Is the instrument used for marking position of plantation at specified spacing. The instrument consists of pegs at equidistance at specified spacing of plantation with handle at center. The spa cement marker is operated across the centering starting from one end with reference to the last point as first point for the next position. The point where cross line matches to the center line, that point is for plantation.

PROCESS OF LAYING OUT CONTOUR:

The Process starts from top of the hill. Contour marker is the instrument for laying of contour and marking of contour liner at calculated contour integral. One staff member at one point and another staff member at fullest length which is roughly 12 meter. Once reading is same at both points, two points are marked. First person with staff or follower has not to move tell the contouring between to follower and goes on selecting and fixing points of equal height till he reaches to the original farthest point. This method of measurement is called " Whole to Part" In this method, error is minimized or avoided completely and check is obtained. Once LEADER reaches his original point, then follower becomes LEADER. The process continues till completion of the of particular CCT line. For change in CCT line, contour interval is taken into consideration. Similarly the total CCT lines are marked. Simultaneously, number of CCT lines can be operated for speedy completion of work. All spots are marked with line or by putting a small peg to avoid confusion. Once lines are marked, digging of trench operation is started. To maintain accuracy in digging original marking is kept un-touched and about 5 cm apart. Size of trenches is 60 cm 30 cm Upper fertile layer of soil is deposited on uphill side of the trench and remaining material like murum, boulder of size more than 20 cm on downhill side. Wherever plenty of stones are available, contour bounds are
constructed on downhill side in advance and then digging of trench is started on uphill side of the bund. Trenches are kept exposed to weather for about two months. After this operation, refilling operation starts. In this operation, for refilling goods quality comparatively fertile soil, which is stored on uphill with topsoil layer up to 1meter width of that area is utilized. It is necessary to develop the perfect shape with 55 cm to 60 cm central depth. During transportation of plants from nursery, it is necessary to provide cushion layer of grass to avoid damage to the plant due to shock. The plant should be arranged in vertical position in two layers (maximum) At the time of unloading, it is necessary to take upmost care of seedlings so that minimum damage or injury in caused to the plants. Plants are to be unloaded at convenient places where from transport to actual planting site is easy. They should be arranged in upright position.

PLANTATION PROCEDURE

In draught prone area a nature is very tricky, it may rain torrentially or may not at all for long period. And evenly it rains, there is large dry spell, this is the most critical point to be though at the time of planting. In order to have success, it is essential to protect the plant at initial stage of transplantation during dry spells. The Plantation operation is carried out with optimum management of manpower and time. The plantation team consists of 15 persons with plantation of 750 plants/day. The plantation operation is divided in following stages:

• Centerline marker - 01 - To mark the centerline

• Spa cement marker - 01 - To mark the cross line

• Digger - 01 - For digging poly pot pit

• Excavator - 01 - For removing the soil from ply pot size pit

• Fertilizer - 01 - For specified dosing of fertilizer

• Cutter - 01 - For taking cut from the top to bottom of one side poly bag

• Planter - 01 - For plantation of plants by removing the plastic poly bag.

• Porter - 03 - For transportation of plants of plants to actual plantation site

• Drainer - 01 - For wetting the plants till it is saturated.

The plantation process starts with formation of groups of 15 persons in each group. The plantation area distributed in the formedgroups. After of seedlings, every person transports the plants to plantation site while proceeding for the site. Then three persons are allotted separately for transportation of plants. In order to he success, it is essential to protect the plant at initial stage of transplantation during dry spells For that the ply plants is fully drained with water till all air bubbles from bag are out and the surrounding soil is fully saturated. The excess water for poly bag is removed. Center line of CCT is marked with the help of CENTER LINE marker. The Spa cement marker is operated across the center lien starting from one end with reference to the last point is for plantation. Simultaneously drained seeding are transported and laid all along ridge of the contour on the upper side of the cross, which is actual plantation spot. The diggers dig to specified size followed by excavator. Excavator excavate the pit to the size required for plantation followed by fertilizer, who is spreading the specified does of fertilized in the pit. Then planter is planting the plants by removing the plastic ploy bag and taking the plant on forearm and gently putting from poly-pot to pit. Filling the vacuum with adjoining soil Gentle press are given with hands after placing plant in place. This process continues till completion of plantation. The case study discussed is located near Nandur-khandarmal village in forest survey no. 152, 178, 179.This site is located in Sahyandri hill range near Nasik-Pune highway. Total watershed is covered with only 10 cm reddish murum soil cover. Remaining 10-hectare area is with approximately 25 cm soil cover. The slope of site is 42.63%. Soil work is completed in May 1997. Plantation was completed in July 1997. Before strain of work, people were not residing in down below area of the work due to drinking water problem. Total 100-hectare land was unirrigated and only crops like bajri jawar were taken. After one year of plantation, more than,
100 people has shifted their residence from village to their lands located down below the work. Total 12 no. Of wells were directly benefited due to this CCT work. The unirrigated land turns into irrigated land giving crops like onion, Tomato, Brinjal. The income of the farmers increased considerably. Similarly, 50-hectare soil conservation, 102500 cum water conservation and 50-hectare increase in forest area is an invaluable gain.