Specifications include, but are not limited to: Task 1 – Develop a CE-QUAL-W2 model for Canyon Ferry Lake Modeling will allow for several water quality response variables to be examined simultaneously, any one of which could prove to be the endpoint from which protective nutrient loads and concentrations are identified. The contractor will model towards the following response variables and associated thresholds (many of which are EPA-recommended): 1. Phytoplankton algae levels a. Maintained below a nuisance or undesirable threshold. Example thresholds include concentrations of 10-15 µg chlorophyll a (Chla) per liter, and Secchi depth of < 1.0 m for no more than 7 days per summer 2. Frequency and type of algal blooms a. Severe blooms in excess of 30 µg Chla/L held to > 1 per summer b. Drinking water cyanotoxin levels: microcystin concentrations ≤1.6 µg/L for adults and ≤0.3 µg/L for children c. Alternatively, swimming advisory level for microcystin of ≤8 µg/L d. Reduction of taste and odor forming algae corresponding to reductions of Chla and bloom frequency 3. Phytoplankton successional patterns which minimize HAB development 4. Other water quality limiting factors including DO in the hypolimnion and pH excursions in the epilimnion, in accordance with Montana’s water quality standards Offerors responding to this RFP are encouraged to recommend other water quality variables that can be incorporated in the CE-QUAL-W2 framework, and/or alternative thresholds protective of water quality in accordance with Montana’s water quality standards. These may be used for modeling pending their approval by the department. Task 2 – Provide a final technical report Report must include the following: 1. A calibrated and validated CE-QUAL-W2 model for Canyon Ferry Lake. 2. Identification of the principal response variable(s) and associated threshold(s) consistent with the goals stated in this RFP. 3. Indicate the corresponding phosphorus and/or nitrogen loads and concentrations that can achieve the thresholds.
