Aiming to Improve Water Quantity and Quality

Invasive woody species are rapidly encroaching the Cross TImbers region and are posing a significant threat to water resources. Additionally, the proliferation of this noxious species has created new fuel complexes with the potential to produce high-severity fires. 

 

Prescribed fire is commonly considered as a tool for mitigating woody species expansion and reducing wildfire risks; however, there remains a critical knowledge gap regarding impacts on water yield and quality. As a result, land managers and natural resource agencies hesitate to use prescribed fire in water supply watersheds. 

 

Why Improve Water Quantity and Quality?

An adequate and sustainable water supply is a crucial factor constraining the social and economic development within the rapidly growing Cross TImbers region. The majority of land in major water supply areas of the Cross Timbers region historically is rangeland; however, with recent increased encroachment rates of woody species, there is growing concern. Woody species are negatively affecting water resources, particularly in terms of water quantity. 

 

A decade-long study in the Cross Timbers region demonstrated that reducing or eliminating encroaching tree cover through mechanical removal stimulated increased herbaceous growth and water yield from small watersheds. Our hypothesis is that the application of prescribed fires can potentially aid in enhancing the water quality, as well. 

 

What is Prescribed Fire?

Prescribed fire, also known as a controlled burn, is a planned and controlled application of fire to land - conducted under specific conditions - to achieve specific land management objectives. Objectives can range from reducing wildfire risk to restoring ecosystems or improving wildfire habitat.

 

Before European settlement of America, relatively low intensity wild fires occurred every 4-6 years in the Cross Timbers region. With increased fire exclusion and suppression in the 20th century, the feedback between fine fuel and fires has been disrupted resulting in significant changes in vegetation composition and increased fuel load in the region. Over recent decades, the reintroduction of fire in the ecosystem has been recognized as an effective strategy to lower fuel loads and aid in control of woody plant encroachment. 

 

Prescribed fire is commonly considered as a tool for controlling woody plant encroachment and reducing wildfire risks. This project is investigating the effect of prescribed fire on water quantity and quality in the region, including the potential of an increased amount of total suspended solids and nutrients in waterways after a fire. 

 

Partners of the OWRC

Oklahoma State University, Natural Resources Ecology and Management

 

This work is supported by Bureau of Land Management grant number L24AC00319.