| Assessments of watershed-based restoration efforts are rare. Monitoring of projects pre- and post-treatment are essential for the science of stream restoration ecology to advance. We took an experimental approach, following adaptive watershed management principles, to evaluate the effectiveness of watershed-based restoration efforts developed to maximize the ecological recovery of acid mine drainage (AMD) impaired streams. We sampled water chemistry, physical habitat, and benthic macroinvertebrate and fish community structure in 3 stream types: AMD (14 streams), AMD-treated (13 streams), and unimpaired reference (4 streams). Treatment technology implemented on impaired streams included in-stream active treatment dosers, limestone sand applications, and an at-source passive treatment system. Assessment sites were strategically selected based on treatment locations, and we evaluated conditions pre-treatment and 3 years post-treatment. Water chemistry varied widely. Sites impaired by AMD improved in water quality with AMD treatment. For example, dissolved metals and acidity declined but treatment waters remained elevated in sulfate and conductivity. Likewise, biotic conditions varied widely and sites impaired by AMD improved in bio-condition scores with AMD treatment. For example, EPT genera increased but were still low compared to unimpaired stream types. In addition, we found fish at 9 sites that previously had none. Community-level analyses indicated improved but altered assemblage of taxa at treated sites compared to untreated sites. Overall, general improvements in water quality and bio-condition at the stream-scale were associated with improvements in a measure of ecological value at the watershed scale. Our results suggest that unique communities driven by the new water chemistry signature are being formed. Only 3 years have passed since project completion and communities that reflect true reference may require more time. This general framework for adaptive watershed management developed for mined watersheds can also be applied to other anthropogenic impacted watersheds in this region. Applying an experimental approach towards restoration project assessments can facilitate restorationists and project managers to understand what types of treatment accomplish their goals. |
