Identifying and assessing the potential hydrological function of past artificial forest drainage

Area of Science:

• Forestry
• Hydrology
• Environmental Science

Background:

• Forest wetland drainage for timber production alters stream hydrology and water quality.
• Ditch network maintenance (DNM) is proposed, but balancing timber benefits with environmental impacts is challenging due to a lack of clear guidelines.

Purpose of the Study:

• To prioritize DNM by quantifying ditches based on soil type and modeling their water flow potential.
• To provide data for balancing DNM with environmental considerations in forested catchments.

Main Methods:

• Quantified forest ditches by soil type within the 68 km² Krycklan Catchment Study area.
• Utilized upslope catchment area algorithms and high-resolution digital elevation models to determine ditch flow potential.
• Mapped and modeled ditch function using laser scanning technology.

Main Results:

• Forest ditches nearly doubled the stream network size (178-327 km).
• 17% of ditches were located on well-draining sedimentary soils, suggesting DNM may be unwarranted.
• Modeling indicated 25-50% of ditches may not consistently support flow.

Conclusions:

• Simple mapping and modeling methods can effectively locate and assess the function of forest ditches.
• These methods facilitate informed decisions for DNM, balancing timber production goals with environmental protection.
• The study provides a framework for prioritizing DNM to mitigate negative impacts on waterways.