Introduction
The beautiful island of Bali is facing a growing water crisis. As populations increase and land irrigation demands more water, the island’s groundwater supply is under immense pressure. Deforestation, a common side effect of development, further exacerbates the situation, increasing surface temperatures and creating drier microclimates. It’s essential for builders and homeowners to understand these challenges and implement water-saving strategies in construction.
Understanding Water Tables
The water table, the subsurface boundary between saturated ground and unsaturated ground, is critical to Bali’s water supply. Its depth varies based on several factors, such as soil porosity, vegetation, and sea level. In Bali, the water table fluctuates with the seasons, rising during the wet season and falling during the dry season. With the end of the dry season approaching, serious water issues are becoming apparent. Most of the water supply comes from wells and bores, which must be deep enough to reach the water table. Shallow wells may draw brackish or contaminated water. Deeper bores typically provide cleaner water.
The Impact of Drainage
Good drainage, while seemingly beneficial, can be disastrous for water tables. In urban areas, the vast majority of land is covered by impermeable surfaces like roads, roofs, and parking lots. This infrastructure directs rainwater directly into drains, returning it to the sea and preventing it from replenishing the groundwater. Similarly, swimming pools and garden irrigation also contribute to the problem by increasing evaporation. In Bali, this issue is compounded by the increasing use of swimming pool and water filtration equipment that require regular backwashing, which discharges large volumes of water into drains.
Consequences of Water Shortages
The water crisis in Bali is worsening, with hotel water supplies drying up. In coastal areas, excessive groundwater extraction can lead to seawater intrusion, contaminating the water table and causing structural damage to buildings due to salt deposits. Throughout the island, groundwater levels are falling, and wells and rivers are drying up.
Strategies for Sustainable Construction and Water Conservation
To address the impending water crisis, we need to embrace sustainable water conservation practices. Here are key actions that can be taken for building and maintaining sustainable properties in Bali:
- Install soak pits: Direct rainwater and greywater from showers and washing machines back into the ground using soak pits.
- Rainwater Harvesting: Install large water tanks under houses to collect and store rainwater, which is free of calcium, sewage, and mineral contamination.
- Water Usage Timing: Water gardens during the cooler hours of the evening or early morning to minimize evaporation.
- Pool Practices: Avoid large swimming pools and ensure pool backwash water is directed to soak pits instead of drains.
- Water Purification Systems: Check your purification system to ensure it does not use excessive backwash water, and make sure that it is not being sent into drains.
- Install Water-Saving Fixtures: Use dual-flush toilets and reduced-flow shower heads.
- Plant Trees: Strategically plant trees to provide shade, reduce ground temperatures, and minimize evaporation.
Conclusion
Every resident and builder in Bali must recognize their role in managing water resources. By adopting sustainable practices like using less water, and returning water to the ground through soak pits, we can all contribute to maintaining healthy water tables. It is imperative that we act now to ensure the long-term sustainability of Bali’s water supply.
