Alterations of Water Availability, Water Quality and Fish Habitats in Cold Regions by Climate ChangeEPA Grant Number: R824801
Title: Alterations of Water Availability, Water Quality and Fish Habitats in Cold Regions by Climate Change
Investigators: Stefan, Heinz G. , Fang, Xing
Current Investigators: Stefan, Heinz G.
Institution: University of Minnesota , Lamar University - Beaumont
Current Institution: University of Minnesota , St. Anthony Falls Laboratory
EPA Project Officer: Chung, Serena
Project Period: October 1, 1995 through September 30, 1998
Project Amount: $300,000
RFA: Regional Hydrologic Vulnerability to Global Climate Change (1995) Recipients Lists
Research Category: Global Climate Change , Ecological Indicators/Assessment/Restoration , Water , Climate Change
Description:The project goal is to develop and apply computational simulation methods which link hydrology, water quality and fish habitat in lakes and streams to climate conditions. Cold regions and their migration to higher latitudes or altitudes under climate warming are the regional focus of this research. Projected climate warming is expected to have a particularly strong impact on ecosystems and aquatic resources in cold regions, particularly water availability and fisheries.
The systematic method of approach has been developed. Water quality is simulated by deterministic, process-oriented, unsteady models. Criteria for fish response to water quality are then used to determine habitat volume or area and fish productivity. The methodology is being extended to winter simulations, i.e., low temperature tolerance criteria for fishes and related ecosystem components. Validation and application is necessary to project changes subsequent to potential global climate change, for example, shifts in fish habitats, the potential for invasion of warmwater fishes into these habitats, the changes in ice conditions, etc.
Preliminary results include development of an ice cover submodel which is used in a lake water quality model to project climate change effects on lakes, especially small lakes with surface areas up to 10 km2 and depths up to 24m in the cold regions of the contiguous United States. The two main parameters studied are lake water temperature (T) and dissolved oxygen (DO) concentration, which are most directly influenced by climate and which in turn have much influence on aquatic lifeforms, water quality, and water uses. Information will be obtained on evaporative water losses from lakes, ice covers on lakes, and sediment temperatures below lakes.
The basic simulation results are 19-year averages of daily water temperatures and DO profiles in lakes, ice thicknesses, evaporative water losses, sediment temperatures, etc. From those results more easily interpretable and useful parameters were extracted, e.g., duration of ice cover, water temperature maxima and minima, DO maxima and minima both at the surface and the bottom of a lake. They were related to three independent lake parameters: surface area, maximum depth, and Secchi depth. Maps of the U.S. giving the geographic distribution of each dependent lake parameter were then prepared.
To include climate change effects in the watershed into lake models, the relationship between runoff and climate in two small watersheds in the mid-continental U.S. is being examined. A parametric runoff model has been developed and applied to two watersheds with substantially different climates. For streams the watershed input makes the climate effect more difficult to capture. Mean monthly stream runoff can be simulated well, if four calibration parameters are used for the watershed. Stream temperatures are well correlated with air temperatures at the monthly and weekly timescales.
Through modeling we can quantify how aquatic systems respond to climate, particularly winter changes. The results include, but are not limited to information on cold region lake quality characteristics, streamflows and stream temperatures, periods and thicknesses of ice covers. The results so far show that one can model climate effects on significant lake water quality parameters. Overall the results indicate that simulations can proceed to fish habitat and water availability estimates.
In the next steps, the lake simulations need to be validated in one or two other regions, and then the 2xCO2 climate scenario needs to be applied at the continental scale. The fish habitat parameters need to be extracted from the temperature and DO simulation results. Upper thermal tolerance criteria need to be applied for coldwater and coolwater fish species. Lower thermal tolerance criteria need to be developed for warmwater fish species.
In the final analysis, the responses to the 1xCO2 (past) and 2xCO2 climate scenario can be compared and an assessment of potential climate change effects can be given.