The Arikaree River, located on the Great Plains of Eastern Colorado, is a principle tributary of the Republican River. The Arikaree contains a relatively intact native fish assemblage making it an ideal system for study and conservation.

My Ph.D research focuses on the effects of groundwater withdrawal and drought on native fishes in Eastern Colorado plains streams. Intensive groundwater withdrawal for irrigation over the past century has led to significant declines in groundwater levels, and in rivers with high groundwater connectivity such as the Arikaree River, to decreased annual discharge. This has led to decreased connectivity among the spawning, rearing, and refuge habitats vital for the persistence of native fish populations. My research will focus on investigating the linkages between pumping for irrigation, groundwater, and fish habitat, and the response of the fish assemblage to groundwater withdrawal and drought. Also of interest is investigating the life history components of brassy minnow (Hybognathus hankinsoni), a state threatened species. The ultimate goal of this project is to make recommendations for conservation and management of native fishes in the Arikaree River basin in the context of pumping and drought.

 

Here are some pictures taken during the 2005 sampling season.

 

Much of my sampling in 2005 consisted of collecting fish larvae (left) and measuring spawning habitat (right). The larval life-history stage of fishes in the Arikaree may be particularly important because spawning habitats (backwaters) begin to disappear as the season progresses. This is due to natural drying and may be exacerbated by groundwater withdrawal.

 

I am also interested in the hydrogeology of the Arikaree basin, particularly the interaction between groundwater and surface water, and the linkages between groundwater, pumping, and fish habitat. To quantify groundwater levels near the river, I installed monitoring wells (left). By developing a model that links groundwater levels to habitat area (or volume) I hope to be able to predict available fish habitat in different scenarios of pumping and drought. Habitat models such as this are particularly important to the conservation of native fishes on disturbed landscapes, such as the Great Plains (right).