Infiltration wells are holes made to collect rain water that does not flow out of the yard. Usually the water from the roof of the house and of the rest of the house dipekarangan is passed into one or more according to the number and capacity of the well. This is very important catchment wells made in dense residential area that topographinya slopes like area Puncak, Bogor, West Java, Batu Malang and other similar areas of settlement conditions.
Water catchment wells is engineered water conservation techniques that are a building which is made such that it resembles the shape of wells with a certain depth which serves as a rainwater on the roof of the house and into the ground meresapkannya (MoF, 1994 at http: //klastik.wordpress .com / 2008/02/04 / prevent-flood-with-the well-infiltration / (Tgl24 December 2010)
Furthermore, the benefits of water catchment wells are:
– Reduce runoff and prevent puddles in the yard, so as to minimize the possibility of flooding and erosion,
– Maintaining groundwater levels and increase groundwater supplies,
– Reduce or withhold the intrusion of sea water for the area adjacent to the coastal areas,
– Prevent the decline or subsidence of the ground as a result of excessive ground water extraction, and
– Reducing the concentration of groundwater contamination
Construction Air Infiltration Wells (SRA) is an alternative in dealing with flooding and declining ground water level in the area of housing, for consideration:
a) the manufacture of construction CFS does not cost much,
b) does not require a large area, and
c) SRA simple form of construction.
To make the recharge wells need to take into account extensive rainwater catchment will be collected disumur and capacity of the wells. Stages to make the recharge wells according to the following:
a. Conduct an analysis of rainfall;
Analysis of the rainfall for the purpose of calculating the maximum precipitation intensity in the period specified. By knowing the maximum precipitation intensity recharge wells, the capacity can be calculated.
- Calculating the rain catchment area;
Together with the maximum precipitation intensity with a certain return period to determine the flow rate.
- Analyzing layers of soil / rock;
Subsoil consists of various layers ranging from soil belempung, argillaceous sand and gravel or a combination of these layers. Recharge wells would be very efficient if it is made up in the area with a layer of rock that is composed of sand or gravel.
- Well construction;
Infiltration wells can be built using the bus with a layer of porous concrete or bricks are arranged regularly.
To construct infiltration wells in order to provide optimum benefits required calculation method (Sunjoto, 1992 in) as follows:
– Calculating water discharge as a function of the characteristics of roof area of the building with a rational formula (Q = CIA, Q = debit entry, C = flow coefficient (types of roofs), I = intensity of the rain, A = area of the roof)
– Calculates optimum depth of the well formulated as follows:
H = Q / FK [1-exp (- (FKT / PR2)] H = water depth (m) Q = Debit entry (m3 / s) F = Factor geometric (m) K = permeability of the ground (m / sec) R = Radius wells. T = Length flow (dt).
b. Evaluate the types of functions and layout pattern of wells at a distance of interplay to determine the depth corrected by using a multi-well system.
Technical data water catchment wells issued by PU Cipta Karya is as follows:
– The maximum size of a diameter of 1.4 meters
– The size of the inlet pipe diameter of 110 mm
– The size of the overflow pipe diameter of 110 mm
– Measuring depth of 1.5 to 3 meters
– The walls are made of masonry or concrete block from a mixture of 1 cement: 4 sand without plaster
– infiltration wells cavity filled with stones as thick as 40 cm blank 20/20
– Closing infiltration wells of 10 cm thick concrete slab with a mixture of 1 cement: 2 sand: 3 gravel.