Objectives
Objectives are defined for the AHP Case Study in order to evaluate the solution students arrive at for each design criteria introduced in the Problem Statement. The three design criteria include: hydrology, wetland design, and hydraulic design. Each of these has been addressed with a single objective and specific tasks that are associated with each objective. More detail regarding these tasks is included in the Design Procedure.
HYDROLOGY
Objective: According to the City of Auburn Storm Water Management Manual, the proposed hydrology must maintain or improve hydrologic conditions at the outlet of AHP for the 2, 5, 10, and 25-year, 24-hour storm events.
Tasks:
1) Determine the runoff volume and peak discharge for the existing hydrology of AHP for storm events of interest.
2) Determine the runoff volume and peak discharge for the proposed design hydrology of AHP for storm events of interest.
3) Alter the proposed design as necessary to ensure that the proposed design runoff peak discharge is less than or equal to that of the existing hydrology.
WETLAND DESIGN
Objective: Design a storm water wetland that a) retains runoff from AHP b) treats runoff for the target contaminants (nitrogen and phosphorus) and c) supports an ecosystem that is diverse, sustainable, and resilient.
Tasks:
1) Determine the parameters of the storm water wetland that are necessary to retain 100% of the runoff volume of 95% of all storm events.
2) Design and draw the wetland including deep pools, shallow water, shallow land, and upland areas.
3) Model the continuous operation of the wetland including: evapotranspiration, deep percolation, and vegetation growth.
HYDRAULIC DESIGN
Objective: Design hydraulic structures that a) route overflow in a manner that protects the wetland ecosystem from degradation and b) provides sufficient baseflow to sustain the wetland throughout the year.
Tasks:
1) Select the number and type(s) of inlet and outlet structures that are needed to support the ecosystem of the wetland.
2) Design and draw hydraulic structures that consider all of the following: drawdown time, detention time, and flow energy.
3) Model the hydraulic structures you have designed and check the required storm events along with both the 50 and 100-year storm events for failure.