Water Quality Considerations in Restoration

Year: 2023
Presenter/s: Ken Vigil
Symposium Session: 2023 - 03 Water Quality Considered in Restoration Design & Watershed Management
Topics covered: lessons learned, stormwater, temperature, urban, and water quality


Many of our restoration efforts in the Northwest and beyond are focused on fish (salmonids, in particular) and their habitat. However, one of the key habitat elements for fish and other aquatic organisms (the quality of their waters) is often overlooked. This presentation introduces some of the most important aspects of water quality/chemistry and the effects of climate change and restoration efforts on water quality conditions.

The physical, chemical, and biological properties of water are defined by water quality parameters such as temperature, pH, dissolved oxygen, biochemical oxygen demand, bacteria, solids, metals, and toxics; and these parameters are regulated by key water quality regulations like the Federal Clean Water Act and the Endangered Species Act. The author will summarize key parameters and regulations to provide a foundation and vocabulary for the discussion.

He will describe some of the water quality aspects of climate change. For example, global warming is increasing the temperature of fresh and marine waters, which is dramatically affecting water chemistry; and wildfires are causing significant degradation to water quality.

The bulk of the talk will include practical examples of water quality considerations on restoration projects in the Pacific Northwest. The presenter will put water quality in perspective for restoration professionals by discussing many of the topics listed below (as time allows) based on past and ongoing projects, and decades of experience.

Water surface area considerations for temperature
Providing additional shading through planting and large wood design
Water depths in restoration
The importance of alkalinity in pH buffering
Aeration in restoration for dissolved oxygen
Side slope design for excavation areas
Sediment and turbidity management during construction and after
Pollutant removal mechanisms in restoration (biodegradation, filtration, sorption, sedimentation)
The impact of temperature, nutrients, and algae on pH fluctuations
Marine and fresh water chemistry changes due to climate change (temperature, carbon dioxide, alkalinity)
Riparian buffers for water quality control
Mitigating water quality impacts from wildfires