Any entity proposing to impact aquatic resources in the state of PA has to apply for a chapter 105 water obstruction and encroachment permit. For small projects such as bank stabilization, agricultural ford crossings, driveway culverts, etc. general permits are available that are cheaper, less intensive applications and reviewed within a shorter timeframe than project requiring a joint permit. Joint permits are needed for projects that alter flood elevations, significant wetland impacts, large scale stream/floodplain restoration, etc. In watersheds that support wild trout, greater protection exists for hydraulically connected wetlands, time of year restrictions from instream construction are implemented to protect spawning trout. This is a relatively basic overview of chp 105 permitting as referenced in the article.