This page is for synthesizing strategies for developing 1) drinking water and 2) irrigation water, at a restoration camping site in the Spanish Altiplano. This site is a 5 ha demonstration site at approximately 1000m in the Arid South of Spain.
Site Description
- There are locality and detailed site maps.
- Here is a 16-year rainfall record describing erratic rainfall patterns.
- Only a 5 ha site is managed by the campers.
- Surrounding lands are managed by other farmers.
- A water harvesting system has been installed with a series of off-contour swales feeding into a series of four ponds.
- The ponds are located along a valley line, receiving flow from an approximately 200 ha catchment.
- There are wetland indicator plants in the valley.
- The soils have a high clay content.
Observed Problem Description
- Water salinity in the ponds is increasing over time.
- There are long gaps between rainfall (see precipitation analysis at the end of the map page.)
- The smaller and lower ponds are more saline (4000 ppm) then the upper ponds (800ppm).
Objectives
- Develop a potable water supply on the site
- Develop irrigation water supply on site that won't make soil saline.
Key Assumptions/Questions/Hypotheses
- Why is the water getting more saline over time?
- Ground water is saline and is interacting with the ponds?
- Verify groundwater salinity by sampling groundwater uphill of pond?
- Why are small ponds more saline than large ponds?
- Higher evaporation rate, but they are 5 times as salty?... that's a lot of evaporation!
- Why do you need to have potable water stored on site?
- The project aims to demonstrate how people can reside on degraded lands as part of restoration.
Solution Alternatives
- Water-tight cisterns for storage of potable water.
- Solar distillation for survival levels of potable water.
- Let saline water flow through a polytunnel growing edible halophyte plants or fungi.
- Reduce evaporation with shade cloth or living canopy or windbreak
- Reduce evaporation with impermeable cover.