Establishment of a Rain Water Harvesting System at Boosa Maha Vidyalaya, Galle, Sri Lanka

Project AreaBoosa Maha Vidyalaya, Galle
DurationJune - August 2010 (2 months, Project Completed)
Funded by Stichting Waterhelp
Objectives This project was to install a rainwater harvesting system with following objectives;
  • To improve the availability of water resources to irrigate an acre of arable land, belonging to the school. Presently this land is used to grow variety of local vegetables and salads as well as few high value Mediterranean crops. While the growing of local vegetables are educational and used to supplement the feeding of the children (providing a free mid day meal) other than the harvesting of high value crops such as salad varieties, herbs are aimed at increasing income towards activities and welfare of the children
  • To reduce the cost of pipe borne drinking water being used to flush toilets
  • To reduce the cost of pipe borne drinking water being used to water the vegetable garden
  • To reduce the negative impact on pH level of the soil as the pipe borne water carries chemical residue (high levels of hardness to protect piping
  • Harvest the rain water for vegetable gardens and maintaining of toilets in an area which is described as wet zone with an annual rain fall of 2540 mm
  • Educate the children of importance of rain water harvest and it's benefit. Usage of environmentally friendly cost free source of water
  • Make the school as the model school in the region in agriculture education
Activities and Results achievedFigure 1, shows the final implemented RWH system including the roofs that were used and connection to collecting tanks. The excess overflow (when the collecting tanks are full) of the 3 cement tanks were connected to the well. In this way as much rainwater as possible would infiltrated thus building an extra groundwater buffer for drier times.

Figure 1: Plan of the final implemented RWH system at Boosa School
1. Installation of the Valence Boards Activity: Not all roofs on the Figure 1 had rainwater gutters. These were installed, but some of the roofs also did not have the required valence board to attach the gutters. This was the first phase of the project and was undertaken by Boossa School.
Results: Boosa School installed valence board on the roof areas of RA 3, 5, 8, 9 and ½ of RA11.
2. Installation of the RWH systemThe work commenced on the 7th of June 2010, in consultation with Boosa school. RWH system designed for the school was modified to accommodate the changes requested by Boosa school to the original plan.

Activities: Following is a list of activities that were carried out.
  • Guttering: Some of the required roofs were to be guttered
  • Tank types: Rainwater run-off from some of the roofs were to feed 5 on-the-spot handcrafted 8m3 ferro-cement tanks and the other roofs feed into smaller 3m3 plastic tanks
  • Filters: Each tank is to be protected from dirt by a Debri Filter, of which the filter material is made of natural products
  • Overflows: The overflows from the five larger tanks were directed to the existing well. The overflows of the smaller tanks were directed to nearest drainage channel to prevent uncontrolled overflows that may cause erosion.
  • Pipes: All piping, including the ones that run to the end-user stations (gardens and poly tunnel) are slightly running as much as possible underground.
  • Poly tunnels: Pipe will supply the poly tunnel and will end in a tap attached to a pole.

Results: Following are the results of these activities.

  • Gutters were installed in Roof areas RA3, RA5, RA8, RA 9, ½ of RA11 (named in figure 3).


  • Photo 1: Gutters installed

  • Tank No. 1 was placed in a elevated base and was fitted with 2 extra taps, class room sink and one outside (to take the balance water not reached to the sink).

  • Tank no. 2 supply water to staff quarters.


    Photo 2: Tank No 1 providing water to class room sink

  • Tank No. 3, 4, & 5 was connected and pipeline was provide to a tap stand near the poly tunnel.


  • Photo 3: Tap stand near poly tunnel


    Photo 4: Tank No. 5


    Photo 5: Tank No. 3 & 4

  • Tank No. 6, collecting from the roof of the toilets ½ RA 11 provide water to the pineapple garden below by a separate tap stand.


  • Photo 6. Tank No 6

  • Tank No. 7 & 8 are connected to a new tap stand distributing water from these two tanks located near the toilet.


  • Photo 7: Tanks 7 & 8

  • The cement tank No. 9 distributes water to the urinals below.


  • Photo 8: Tank No. 9


    Photo 9: Urinals

  • The plastic tank 10 connects to the pipe stand nearby, providing water for gardening.


  • Photo 10: Tank No. 10

  • The plastic tank 11 placed on a base and connected to tap stand near by to provide water to the gardens and to the Principal's toilet.


  • Photo 10: Tank No.11

  • All tanks are fitted with a stop valve, therefore each tank can be operated separately for cleaning and maintaining purposes.


  • Photo 12: Stop valve

  • The stop valve at tanks no. 3,4,5,6,7,8 and 9 is protected by a gully with a lid to prevent damage.


  • Photo 13: Gully

  • Each tank is fitted with derbies filter which contain pebbles and charcoal as filter media in a plastic bucket or basin and a mesh covering it to prevent entering of mosquitoes.


  • Photo 14: Debris filter for cement tank


    Photo 15: Debris filter for plastic tank

  • Overflows of tank No. 5 and 6 are connected to the well for ground water recharging. Overflows of all other tanks are connected to the near by drains and covered with mesh to prevent entering of mosquitoes and other animals into the tank.


  • Photo 16: Over flow of tanks

  • Tanks 1,2,3,4, 5,6 and 9 is fitted with a first flush devise, so that any dust collected in the roof is first discarded before it enter the tank.

3. Awareness programActivity: The awareness program consist of two parts:

1. A maintenance training performed by LRWHF prior to commissioning;
2. An awareness program conducted by the school to the pupils and teachers

Results: LRWHF masons instructed the workers on operation and maintenance of the system during construction.
4. Maintenance programActivity: The awareness program consist of two parts:

  • Instructions how to keep the first flush system ready to collect the first dirty water from the roofs, and how often to do this;
  • Instructions on how to clean the two different tanks;
  • Instruction how to clean and/or replace the materials of the debri filters at each tank;
  • Explaining by showing in reality what maintenance is required and how the debris filters should be cleaned;

Results: Instruction manual on how to operate the first flush, clean the filters and clean the tank was handed over to the School Principal along with leaflets and Manual of rain water harvesting in Sinhala

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