by Lovely A. Carillo
FOR DECADES prior to the 70s, millions of Dabawenyos depended on rainwater for drinking, cooking, washing and most other uses because the vast reservoir of water – the aquifers – had not yet been tapped. Diarrhea and other water-borne diseases as well as dental caries were common in the city. This was before the birth of the Davao City Water District in 1973.
Very soon, Dabawenyos will be back to extensive use of rainwater for a different reason – to conserve its tap water, reputed to be the best in the world in quality, second only to that of The Netherlands.
Aside from conserving underground water stored in the city’s aquifers, Dabawenyos will also be saving millions, if not billions, of pesos in water expenses if the Davao City Rainwater Ordinance is finally enforced.
The measure, proposed by Councilor Leonardo Avila III as early as five years ago, has been approved on Second Reading, which makes the proposed ordinance as good as approved.
The Avila ordinance, which provides for “Proper Harvesting, Storage and Utilization of RainWater, would require diehard environmentalists and nonconservationists alike to install rainwater containers in their homes or establishments for washing and bathing purposes, watering their plants and other uses other than drinking.
Avila got added inspiration from hotels in Bangkok, Thailand which are able to utilize rainwater for shower purposes of their clients.
“I was there recently for a conference and I was amazed to find that the hotel where I was staying offered a rainwater option in the bathroom,” Avila said.
Avila said the harvesting of rainwater is actually a sustainable approach in the management of water resources in light of climate change. No less than international organizations like the Food and Agriculture Organization and the United Nations have recognized and recommended rainwater harvesting as a sustainable method of preserving water.
“The extensive use of rainwater will go a long way in supplementing the supply of water, especially in areas where there is a limited source of groundwater,” he said. This will also prevent over extraction of groundwater resources, he added.
Harvested rainwater can be used as a strategy to reduce flooding incidents since it reduces runoffs to storm water drains. It can be used for irrigation in both urban agriculture and gardening. It can also be used for domestic, commercial, institutional and industrial purposes.
Avila said Davao City is lucky because it has one of the world’s best potable waters. However, he said, even Davao can face the reality of a water crisis if Dabawenyos would resort to water wastage without implementing water-saving strategies like rainwater harvesting. The entire country, he said, relies mainly on groundwater resources but this can be depleted with over exploitation.
At least 97% of the water production by the Davao City Water District is sourced from groundwater. The DCWD supplies the water demands of the city’s residential, commercial and even industrial users, Avila said, and this demand is expected to increase with population increase and economic boom.
An average household makes use of only 35% of fully treated water for drinking, bathing, cooking and washing the dishes, compared to the 65% used for general cleaning, flushing the toilets, gardening and washing of clothes. Avila said the latter consumption methods can already be supplied by harvested rainwater, which can be a big chunk off our requirement for clean potable water from DCWD.
“This should translate not only to making water more sustainable but in keeping your water bills low,” he said. Even public elementary and secondary schools, as well as coastal and rural households with limited groundwater sources, can take advantage of rainwater harvesting and improve their sanitation in the process.
While his colleagues in the city council lauded Avila’s Rainwater Collection Ordinance, there were doubts as to its legality, particularly the need to amend the Building Code. Councilor Bonifacio Militar questioned the provision of the ordinance which requires the setting up of a rainwater catchment system as a condition required for the granting of a business permit.
Councilor Teresa Marañon was, however, more concerned about forcing people to comply with the system or face the penalty if they are not able to comply with it. Marañon suggested that instead of penalizing the violators, why not provide incentives for those who will comply? Councilor Karlo Bello questioned the wisdom of providing a common penalty for the residential, commercial and industrial sectors.
Avila said harvesting rainwater is already a step towards minimizing the effects of flooding in the city in the light of climate change. Collecting rainwater, he said, reduces surface runoff, siltation and flooding.
Just like other environmental measures, the harvesting of rainwater requires the putting up of the RCS which consists of the collection system or the catchment surface, the conveyance system such as the gutter and downspout and the storage system to include storage tanks. One will also need a treatment and disinfection system and drainage or sewerage system.
Avila said putting up the rainwater collection system (RCS) is not too expensive and may only cost about P5,000 for the average home. RCS can be equal to or less than 50 square meters. “The size of your catchment area is actually the same as the size of your roof,” he added.
