Land use planning to protect drinking water – an integrated approach to hydrographic basins in a changing environment.

  • Date: 01/01/2020 – 31/12/2022
  • Project Manager at NEIKER: Nahia Gartzia
  • Total budget: 101,000 Euros
  • Department: Forestry Sciences
  • Partners: NEIKER

“Increasing demand for food, water, materials, and energy through practices that are adapted to an uncertain future and that mitigate climate change, reverse environmental degradation (including loss of biodiversity), and promote efficient nutrient use and soil protection are interconnected challenges we face as a society. In this sense, forests play a central role in providing raw material for bioeconomy and drinking water.

Forests provide high quality water by minimising soil erosion, reducing sediments in rivers and filtering other pollutants. Nevertheless, guaranteeing quality water availability is reason for growing concern in industrialised countries. High concentrations of certain disinfection by-products like trihalomethanes (THMs) and illudane type phytotoxins such as ptaquiloside (PTA) in drinking water represent a human health threat since both are carcinogenic. THMs form due to the use of chloride in drinking water disinfection since it reacts with the dissolved organic carbon (DOC). DOC in raw water is related to management practices, vegetable covering, topography, climate and soil type.

In organic soils in places with high rainfall and under conifer forests with gentle slopes, DOC concentrations in water increase. Likewise, in areas with Pteridium aquilinum, the washing of its brackens cause PTA to enter the environment (soil and water).

On the other hand, DOC concentrations reduce with the increase in depth of mineral soil since water has a long residence period.

In addition, DOC concentrations reduce in soils with high clay or iron oxides/hydroxides and aluminium content. Climate change is expected to increase temperatures and accumulation of precipitation which will result in a decrease in average flows at certain times as well as higher concentrations of DOC. This will threaten compliance with water quality standards besides sufficient water supply.”