Research Article Volume 7 Issue No.4 Planning, Design and Estimation of a Check Dam B.H. Ramathilagam1, S. Murugesan2, M. Manikandan3, A. Arumugaraja4, Assistant professor1, U. G. student2, 3, 4 Department of Civil Sethu institute of technology, Virudhunagar, India
Abstract To overcome these issues on a global scale, water erosion is the most severe type of soil erosion. It occurs mostly in the form of running water. This study was to develop information from dam which check dam can be adopted for the purpose of ground water recharge. Dams are constructions built across a river or a stream and used to interrupt and store water for special purpose. Check dams are comparatively smaller and more temporary to other types of dams for the purpose of ground water recharge. The Study consisted of a site selection phase, a surveying phase, an planning phase, an design phase and estimation analysis. .This Particular scheme lies in highly favourable zone for recharge as classified in the zonation map for Ground water recharge. By implementing this scheme, with in the zone of influence of about 1 km radius from the check dam site will be benefitted by way of percolation. Increase the Ground water level and increase the revenue through the ayacut . Totally 185.02.0 Ha Ayacut is benefitted through Seventy Eight No’s of wells. Moreover, all the wells (both domestic and agricultural wells) within the zone of influence will be recharged. The length of the check dam is 106m. The design and Estimation of the structure is done using the software Ms-Excel. The total estimation amount of the project is Rs.248.57461 Lakhs.
Keywords : Ground Water-Recharge, Water Erosion Control, Check Dams, Flow Velocity.
I. INTRO DUCTION consider for selecting a site the water demand and ground water is necessity for cultivate crops and increase revenue and A dam is a barrier that impounds water or underground standard of living afterwards opinion from public and streams. Reservoirs created by dams not only suppress floods grievance should be noted. leveling should be done in the but also provide water for activities such as irrigation, human proposed site with the use of surveying instrument like auto- consumption, industrial use, aquaculture, and navigability. level, tripod, tape, plump bob, thread. Surveying work of Hydropower is often used in conjunction with dams to leveling is carried out from upstream to downstream of the generate electricity. A dam can also be used to collect water river up to 50 M from the site then reduced level of each or for storage of water which can be evenly distributed points should be calculated from height of collimation method. between locations. Site should be cleared from vegetable, leaves, un bushy level Dams generally serve the primary purpose of retaining after foundation should be erected at where the soil is week water, while other structures such as floodgates or leaves are depth up to 3m to 5 m . used to manage or prevent water flow in to specific land regions. There are several types of check dams; each type of dam is constructed with different conditions. In general, some essential considerations of check dams need to be considered. First, the site of each check dam must be carefully inspected to assess dam settling. The slope of waterway should be no more than 50% and the depth to bedrock should be over 2 feet (Department of Environmental Quality, 2005). Second, check dams materials will vary depending on conditions and locations. Logs and rock are usually utilized in permanent or semi-permanent check dams for their stability, and sandbag is for short term purpose (Mississippi Department of Environmental Quality, 2011) This type of dam project can be widely utilized in small open channels and drainage ways, including temporary and permanent swales. Check dams flattens the gradient of Figure 1 channels and blocks streams from fluently flowing. As a consequence, not only the velocity of flow is mitigated, but I. Plan of check dam also the path can be distributed toward vegetation . On another The planning of check dam done should be in two views hand, check dams also trap sediments from streams which A) Half plan at top & half plan at foundation. b) cross -section helps to reduce water erosion. of check dam
II. S ITE S URVEYING A. Half plan at top & half plan at foundation Before starting surveying work to select the area where Half plan from top view and half plan at foundation are the check dam is constructed and some procedures should be shown in fig 2. From top view plan shows apron & of both U/S
International Journal of Engineering Science and Computing, April 2017 6464 http://ijesc.org/ side and D/S side. from left to right half top plan shows figure total discharge through scour vents and over weir 2. U/S Return wall then us bed level +328.280 to crest = 17565.088cusecs +329.480 and stilling basin is 6.40m wide afterwards cement Design discharge for the anicut = 17497 cusecs concrete blocks in right side portion ends is apron in D/S bed level+328.280 and 8.00m wide. D. Stability calculation The stability of body wall of the anicut was checked for the following conditions:
1 Reservoir empty without eq 2. Reservoir at MWL,with tail water with uplift 3.Reservoir at FRL, no tail water with uplift 4.Upstream side fully silted up to crest, No silt/water at D/s side WT @Crest
Figure:2 Half plan at top & half plan at foundation
B. Cross-section of check dam
Cross-section of check dam shows abutments, d/s wing at start ,u/s wing & return, d/s wing at end, d/s wing at basin. 1. Maximum stress= SV/b*(1+6e/b) = 3.5442T/m2 cement concrete 1:3:6 using 40mm aggregate m15 graded Minimum stress = SV/b*(1+6e/b) = 1.0501T/m2 aggregate with surface reinforcement details are shown in figure 3 2. Maximum stress= SV/b*(1+6e/b )=3.5442T/m2 Minimum stress = SV/b*(1+6e/b) =1.0501T/m2
3. Maximum stress= SV/b*(1+6e/b) =3.5442T/m2 Minimum stress = SV/b*(1+6e/b) =1.0501T/m2
4.Maximum stress= SV/b*(1+6e/b) =3.5442T/m2 Minimum stress = SV/b*(1+6e/b) =1.0501T/m2
Regime width = 4.83 sqrt (494.691) =107.5m
Looseness factor = Existing overall length /Regime width = 107.5 M
Scour depth = 3.6 M Stilling basin level = 327.780 m Figure 3 CROSS-SECTION Total horizontal floor length: II. DESIGN Length of u/s floor = 3.00m A. Design the check dam structure The check dam structure design in limit state method. Width of the body wall = 2.50m Design should be followed by the rules of indian standard IS 6966-1973. D/s floor length = 6.80m
B. Rear water calculation Total floor length required =12.30 m To find out the discharge in the rear water calculation by providing stilling basin length = 6.40m applying manning’s formula (i) area (A)=183.478m2 (ii) wetted perimeter (p) =107.054 m (iii)discharge=17497 cusecs. Hence total floor length = 12.30m
C. Front maximum water level F. Downstream protection work
The front maximum water level determines discharge the Length of downstream protection block = 1.5 D amount of water from anicut and back water length calculation =5.7 m : P/ HO 0.65