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Mountain Rain

For many rural communities in the Department of León, access to water is a challenge.  The problem is particularly acute for those communities located in the hills along the chain of volcanoes known as Los Maribios.  With the nearest source more than 5 km away for some, these families face a daily four hour journey on foot or horseback to collect water to meet only the most basic needs, consuming time and energy to the detriment of farming and education.

Following the successful completion of a pilot rainwater harvesting project in El Ojochal del Listón on the slopes of Volcán Telica in 2006, Nuevas Esperanzas developed plans for a far-reaching programme to increase rainwater harvesting and improve watershed management in Los Maribios.  ‘Mountain Rain’ is part of a long-term integrated programme which aims to encourage the development of sustainable livelihoods in seven target communities in an environmentally sensitive area.  The beneficiary communities are Agua Fría, El Ñajo,El Caracol, El Ojochal del Listón, Mata de Caña, El Cacao and Las Pilas, all of which fall within the Municipality of Telica.

Nuevas Esperanzas has promoted the concept of rainwater harvesting since 2005.  Collection of rainwater is sustainable, environmentally friendly, relatively simple and cost-effective and is the only viable solution to the water needs of most of the hillside communities.  The climate of this area is such that plentiful supplies of rainwater can be collected from roofs during the wet season, but the challenge is to store sufficient water to last for the five months of the dry season and to protect this water from contamination.  The systems promoted by Nuevas Esperanzas have large, closed, ferrocement tanks designed to let rainwater in but keep mosquitoes out.  The technique used to construct these ferrocement tanks is simple and only locally available materials and basic hand tools are needed.  The tanks are robust and can last for thirty years or more.  However, the quality of the workmanship is crucial and careful supervision and instruction is essential.

‘Rainwater harvesting for beginners'’

The first stage of the project was to review the design of the rainwater tanks previously constructed and to build a model to trial some improvements and modifications.  The construction of this trial tank also provided an opportunity to train local builders.  This stage of the project was funded by the Oxford-León Trust.  The tank was constructed in the community of Gracias a Dios at the foot of Volcán Telica.

Instead of the traditional design which uses wooden formwork wrapped in barbed wire, the trial tank was constructed by rendering directly onto a welded mesh reinforcement structure wrapped in sacking.  The aim of this and other improvements to the design is to reduce the materials required, to reduce the time needed for construction, to reduce the cost of each tank and to simplify the process as much as possible without in any way compromising the strength or useful life of the tanks.  For every tank built in the remote hillside communities all the materials must be transported up the hill to the construction site.  This presents a major logistical challenge and any reduction to the volume of materials required has a significant impact on the efficiency of construction in the mountains.

Six local builders from the San Jacinto area completed the three week training course in tank construction.  After construction was completed, the group evaluated the new tank and reviewed the modified features to assess what worked well and could be implemented in future tanks. 

Click here to download the final report of ‘Rainwater harvesting for beginners’ (2.57 MB)

‘Mountain Rain – Phase I’

In July 2008, the Georg Fischer Clean Water Foundation approved funding of US$80,000 to support the construction of 21 household and communal rainwater harvesting systems in the hillside communities.  The majority of the household systems were constructed in El Ojochal del Listón as a communal system has already been built at the school in this community.  In addition, communal systems were built in the communities of Agua Fría, El Caracol, El Ñajo and Las Pilas.

One of the recommendations of the evaluation of the experimental tank constructed was that a standard domestic system should be 20,000 litres rather than 23,000 litres.  This is because the walls of the 23,000 litre tank required a little more than two complete sheets of welded mesh to form the circumference which was hard to manage when trying to form a perfect cylinder.  Eleven individual domestic tanks in El Ojochal were constructed at 20,000 litres using two complete sheets of mesh to form the walls.  Shared tanks of 40,000 litres required just under three complete sheets of welded mesh to form the cylindrical tank walls.  Two tanks of 30,000 litres were also constructed.

Construction began on the first domestic tank in El Ojochal del Listón in the first week of February 2009 with around half the community participating.  The idea behind this was to use this opportunity to train as many people as possible in the construction technique.  There is no shortage of manual labour in this community and participation is almost always excellent.  Once the walls of this tank were complete, the community volunteers divided themselves between the next three tanks to start work while the mortar dried on the first tank.  This process was then repeated as work progressed to other parts of the community. 

A significant need identified in El Ojochal del Listón was to improve roofs.  Rainwater harvesting is possible from corrugated galvanised iron, tile and even asbestos-cement roofing, but it is not advisable from traditional palm roofs which have a much lower yield and an adverse effect on water quality.  Around a third of houses in El Ojochal del Listón had only palm roofs and more than two thirds had less than the minimum area of appropriate roofing needed.  Palm roofs were replaced with corrugated galvanised iron, and several families took the opportunity to rebuild their houses completely.

In the other communities, communal tanks were built as far as possible to take advantage of existing communal buildings with large roofs.  In Agua Fría, 40,000 litre tanks were built at two churches on opposite sides of the community.  In El Caracol, a tank was built at the village school.  El Ñajo has no communal buildings, but one 40,000 litre tank was constructed at one of the larger houses for community use.  In Las Pilas, a purpose-built roof was erected next to the tank as the community had for a long time wanted a simple building which could be used a pre-school.

This phase of the project was evaluated according to indicators defined in the project proposal:

·         The project aimed to to reduce the time spent collecting water from a maximum of four hours per day to a maximum of 15 minutes per day.  In this context a distance of less than 100 m to a source is equivalent to a round trip of less than 15 minutes, whilst a distance of 5 km is equivalent to a round trip of 4 hours.  The project achieved this target for all beneficiaries in El Ojochal del Listón.  Note that this target is for the construction of household systems and in the case of the other communities where only communal systems have been built, this target is yet to be met.

·         The project also aimed to increase water use from an average of <15 litres/person/day to >25 litres/person/day, although after further investigation, the baseline water use was actually found to have a mean of 28 litres/person/day.  Assuming that journeys to collect water were eliminated completely, the mean amount of water available during the dry season from rainwater harvesting would be around 35 litres/person/day.  The mean amount of water available from rainwater harvesting as an average of the whole year (including wet and dry seasons) is 54 litres/person/day.

·         Finally, the project aimed to provide water containing 0 E.coli/100 ml in 90% of samples of untreated rainwater (based on WHO guidelines which would classify this level of water quality as ‘Excellent’).  The communities currently draw water from various springs around the hills which were analysed as part of the baseline monitoring.  According to the WHO classification, the overall quality of existing springs sources would be considered as poor as none tested negative for E.coli.  Two sources contained 1-10 E.coli/100 ml (low risk), four sources contained 10-100 E.coli/100 ml (intermediate risk) and three sources (including the most used) contained over 100 E.coli/100 ml (high risk).  In the case of the newly constructed rainwater harvesting systems, 11 of the 21 tanks contained no coliforms, seven tanks contained 1-10 E.coli/100 ml (low risk), two tanks contained 10-100 E.coli/100 ml (intermediate risk) and one tank contained >1,000 E. coli/100 ml (very high risk, though subsequent testing indicated that this result was not representative).  These results are a considerable improvement on the baseline but do not yet meet the target set in the proposal (>90% of samples with no coliforms).

Click here to download the final report of the Mountain Rain project funded by the Georg Fischer Clean Water Foundation (1.33 MB - main text only).

The appendices (12.8 MB) and maps (14.2 MB) can be downloaded separately.

‘Mountain Rain – Phase II'

In July 2010, the American Nicaraguan Foundation approved a grant of approximately $13,500 for the construction of five further rainwater harvesting systems, two in El Ojochal del Listón and three in Agua Fría.  These tanks will be completed by the end of 2010, bringing the total in the Mountain Rain communities to 27.  It is envisaged that around 60 tanks will be constructed in total over the next three years.