Project extended hyporheic zone and floodplain treatment zone boundaries must be assessed with hydrologic and hydraulic models to demonstrate whether it increases water surface elevations or has adverse downstream flooding impacts.
Project must avoid extended ponding / inundation of the floodplain to assess the potential adverse effects of extended open water ponding based on the soil characteristics, plant community, amphibian and other aquatic habitat goals.
Project must demonstrate consideration of potential unintended consequences of the restoration, such as aquatic passage and potential water quality loss. A site impairment exists and that the interventions or restoration work proposed are appropriate to address the impairment. The proposed design should demonstrate that a positive ecological functional uplift (or change) for the stream and associated riparian system will result.
Any wetlands that fall within the boundaries of the floodplain treatment zone and are reported for credit under Protocol 3 should not also be reported using the Non-Tidal Wetlands Expert Panel.
Project meets all of the qualifying conditions listed in the original Stream Restoration Protocol Expert Panel report outlined in Appendix B.
Project must demonstrate that it either provides, or is tied into existing upstream and downstream grade controls to ensure the project reach can maintain the intended stream access to the floodplain.
Project must clearly define the boundary of the effective hyporheic zone. For floodplain restoration and raising the stream bed projects, the EHZ is a maximum of 18 inches deep in the floodplain soil profile, and extends only to those areas that are regularly inundated after the streambed is raised. The actual dimensions must be confirmed by site investigations that define stream flow conditions, root zones, aquifer conditions and the pre-project water table conditions
Project must demonstrate that baseflow conditions are not reduced as a result of the restoration. For example, change from perennial to seasonal intermittent flow.
Confirm the presence of legacy sediment deposits.
Demonstrate that the design approach restores channel and floodplain connection with the hyporheic aquifer and restores processes within a hyporheic exchange zone. The EHZ is a maximum of 18 inches deep in the floodplain soil profile. When modern site constraints prevent directly connecting the restored channel and floodplain to the hyporheic aquifer, the design should include measures to interrupt flow within the hyporheic aquifer and elevate the hyporheic exchange zone into the restored floodplain.
Project has defined EHZ boundaries across channels/floodplain.
Legacy sediment removal is the primary floodplain restoration technique.
Treatable TN :
Treatable TP :
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