Lake Assessment Lab
Recognizing the challenges to the health and functionality of Kansas reservoirs, the Kansas Biological Survey in 2006 began conducting bathymetric (lake bottom) mapping and taking sediment cores at reservoirs throughout the state to set a baseline of information, assess current conditions and compare them to the historical record (as recorded in their sediments) each of these reservoirs.
This initiative has provided critical information concerning the status and conditions of the state's reservoirs, helping state and local officials to make informed decisions about the safety, supply and reliability of our valuable water resources.
The Survey produced complete reports on the lakes it mapped, and many of these reports have been made available publicly via the Kansas Water Office website. In addition, the Survey has created a web map application, Kansas Lakes and Reservoirs, that enables visitors to interactively view the latest data on the physical, chemical and biological conditions in reservoirs and their watersheds that is contained in the reservoir information database.
The current activities of this program, outlined below, relate directly to the following priorities listed in the section beginning on page 16 of the Kansas Water Plan (.pdf):
- Secure, protect and restore our Kansas reservoirs;
- Improve our state’s water quality;
- Reduce our vulnerability to extreme events;
- Increase awareness of Kansas water resources.
For more information about the work of our Lake Assessment team, please contact Ted Harris, assistant research professor.
I. Historical reconstruction of long-term water quality
Each year, sediment and billions of dead algal cells settle to the bottom of Kansas reservoirs, continuously covering the previous year’s deposits. The dead algal cells slowly degrade within the sediment but leave behind pigments unique to distinct algal taxa—including the “blue-green algae” that comprise Kansas’s Harmful Algal Blooms (HABs). Because older sediments are continuously buried by more recent sediments/dead algae, the cores serve as a layered timeline of algal community changes and HAB events over the entire life of the lake.
Since 2017, the Lake Assessment team has reconstructed water quality and HAB events in Milford, Marion, Sebelius, Webster, Kanopolis, Perry and Lovewell reservoirs. This work has shown that HABs have dramatically increased over time in Kansas lakes. In particular, dramatic increases in HABs have occurred in Milford, Marion and Perry since 2000.
II. Large-scale experiments
Harmful algal blooms (HABs) of blue-green algae have occurred in more than 100 public waterbodies in Kansas in the last decade. The Lake Assessment team has conducted multiple large-scale experiments in replicated ponds and tanks at the KU Field Station to:
- better understand what environmental conditions favor HABs and their potent toxins; and
- elucidate ways to mitigate HABs.
Specifically, these large-scale experiments have been used to better understand:
- how blue-green algae and their toxins respond to different sources of nitrogen—a growth-limiting element;
- whether or not blue-green algae blooms can be mitigated by shading;
- how herbicides and pesticides can affect HAB dynamics; and
- the impacts of grassland fire on water quality.
III. Water quality monitoring
There are a multitude of water quality issues in Kansas waterbodies. The Lake Assessment team focuses on monitoring water quality in lakes and streams, especially those with blue-green algal issues. Monitoring occurs with in-lake buoys that collect water quality data every hour or by routinely visiting lakes to collect water samples.
The Lake Assessment team has used water quality monitoring projects to:
- track seasonal HAB occurrence and toxicity;
- help optimize drinking water intake locations;
- elucidate potential in-lake HAB mitigation techniques;
- characterize seasonal E. coli dynamics; and
- better understand lake nutrient loading from inflowing streams.