Building a better world, one community at a time

Rainwater Harvesting at Orkeeswa

 

 

Water Hole

Water in Lashaine Village

No surface water resources (i.e., rivers, streams, lakes) are present in or around Lashaine Village. No groundwater aquifer has been found in the village, therefore well development is not a feasible option for supplying water for Orkeeswa Secondary School.

Villagers rely on rainwater that collects in large “watering holes” during the wet season to provide water for their households. Water becomes very scarce during the long dry season.

 

Water at Orkeeswa

Orkeeswa used to collect rainwater from the classroom roofs and store it in small plastic tanks. The storage volume in the plastic tanks was insufficient to last through the dry season and for several months each year, water had to be trucked in from neighboring areas, diverting significant funds from the school budget.

Additionally, the water that was trucked in is known to contain naturally-occurring fluoride, at concentrations exceeding the maximum levels deemed safe for consumption.

 

Site Assessment

A reliable and clean water supply was identified as a priority for Orkeeswa and rainwater harvesting was deemed as the most appropriate solution, due to the absence of groundwater or surface water sources.

The Tanzania Team conducted a site assessment in April/May of 2009, completing a topographical survey of the site, evaluating local building practices and the availability and costs of building materials, and meeting with local contractors with experience in water tank construction.

Design

The team worked on a phased design of the rainwater harvesting system, coordinated with the planned expansion of Orkeeswa Secondary School campus and growing student enrollment.

Ferrocement tank construction was selected as the most appropriate construction method and each phase of the design included construction of a 60,000-liter tank and a harvesting and conveyance system that conveys roof runoff from school buildings to the tank.

 

Rainwater Tank Drawing

Tank Construction

Bacteria-in-Water Experiment

Implementation

By August 2009, the team had completed the design and secured a budget to construct the first 60,000-liter rainwater storage tank. Team members traveled to Orkeeswa in September 2009 to oversee the construction of the tank, educate Orkeeswa students about water contamination and rainwater harvesting, and provide operation and maintenance training. EWB worked with a local contractor to construct an above-ground ferrocement reservoir, reconfigure the gutter system and install and conveyance system.

Orkeeswa campus expanded in early 2010 with the addition of a new classroom block and science laboratory and more roof space became available for harvesting rainwater. EWB returned to Tanzania in June 2010 to construct a secont 60,000-liter tank. The trip also included installation of a solar energy system at Orkeeswa.

IEFT constructed two additional reservoirs in 2011 and EWB continues to monitor the condition of the rainwater harvesting system at Orkeeswa.