| Freshwater is vital for all life, and with the growth of the human population, the need for this limited resource has increased. However, human activities have significant impacts on freshwater ecosystems, leading to their degradation. In order to ensure that freshwater resources remain sustainable for future generations, it is critical to understand how to evaluate stream health and mitigate degradation. To address these issues, the following research objectives were developed: 1) assess current methods used to evaluate stream health, in particular macroinvertebrate and fish stream health indices and 2) introduces a new strategy to improve stream health to a desirable condition at the lowest cost by optimizing best management practice (BMP) implementation plan. Analysis of over 85 macroinvertebrate and fish stream health indices indicated that the most commonly used macroinvertebrate and fish indices are: Benthic Index of Biotic Integrity (B-IBI), Ephemeroptera Plechoptera Trichoptera (Index) index, Hilsenhoff Biotic Index (HBI), and Index of Biological Integrity (IBI). These indices are often modified to take into account local ecosystem characteristics. In order to address objective two, several hydrological models including Soil and Water Assessment Tool and Hydrologic Integrity Tool were integrated and the results were used to develop stream health predictor models. All of the models were guided by a genetic algorithm to design the watershed-scale management strategies. The coupled system successfully identified eight BMP implementation plans that were resulted in excellent stream health conditions according to the IBI score. |
