Rain Water Harvesting Tips

January 19, 2020

The potential of rain to meet water demands is tremendous as rain water is the ultimate source of fresh water. Hence rain water harvesting can help overcome water scarcity.

Rainwater harvesting is the collection of rainwater for direct use via containers or recharging of existing ground water aquifers for withdrawal later.

The opted route depends on the pattern of rainfall received by the region. Areas which receive perennial rains, rain water harvesting can be done via a domestic sized water tank storing rain water as the period between two spells of rain fall is short. Alternatively, areas which receive rains for 2 to 3 months annually, the rain water collected during the monsoon has to be stored for use throughout the year thereby requiring huge volume storage containers as well as some treatment processes.

Thus, evaluating the benefits of ground water recharge, it often is more feasible to use rainwater to recharge ground water aquifers rather than opt for a storage system.

The amount of water collected by rain water harvesting depends on factors like the annual rainfall received by the region, the total area of collection available and the amount of recharge into the ground.

Rain water can be harvested from roof tops and also from open spaces. Open wells or bore wells if available can be recharged using roof top water. Rainwater available in open spaces can be recharged via other recharge structures.

Rainwater may be collected and recharged into the ground water aquifers through simple and cost effective methods like:

1. Roof top rain water harvesting
   1. Open Well Method
   2. Bore Well Method
   3. Open Space or Roof Top Harvesting
      1. Percolation / Recharge Pit
      2. Percolation / Recharge Pit with bore
      3. Recharge Trench
      4. Recharge Trench with bore
      5. Recharge Well (Small and Large diameter)

These are simple and common methods and can be applied in any combination based on the on ground conditions, sub soil conditions etc.

Rain water can be collected using polythene sheets or rain water from the roof can be collected via gutters. Using PVC pipes, the collected water is passed through a filter. The filtered water is collected in a storage tank, an existing sump, bore well, recharge pit or in an existing open well. This is the very basic process of rain water harvesting.

Depending on the scale of the project additional structures may be required like a filter chamber/sump or settlement/filter tank. The construction of structures like recharge pits may also differ based on parameters like type of the sub-soil etc.

This information has been provided by Eureka Forbes.

Tags: Water Matters

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