CHS Engineers LLC 5/4/2020 - Laserfiche WebLink

2.4.2. Prepare planning-level plan sheet from existing station to east side of Edgewater Park, based on GIS data and site visit observations, to document existing conditions for planning and evaluation purposes. 3. Capacity Estimate and Siting Evaluation 3.1. Capacity Estimate: 3.1.1. Estimate peak hour wastewater flow capacity (sanitary and inflow/infiltration) based on City design criteria and/or City-provided flow monitoring data for dry and wet weather conditions. Confirm sizing of HDPE force main for peak hour flow capacity with minimum velocity of 3.5 feet per second, at full-speed pump operation. Estimate potential range of total dynamic head (TDH) for alternative sites. 3.1.2. Estimate capacity of 480V, 3-phase power service and standby power equipment, for start of one primary pump and time-delayed start of secondary pump, and miscellaneous station electrical loads. 3.2. Siting Evaluation of Alternative Sites 3.2.1. Elements Configuration: identify configuration and approximate footprint of primary elements (station, parking, power and control equipment, standby generator, Bioxide)for each alternative. 3.2.2. Alternatives Screening: Identify up to five potential station sites including the three indicated above and one or two more to be identified in collaboration with the City. Complete a general screening of the alternative sites on the basis of general "pros" and "cons". From the general screening, select up to three alternative sites for the Alternatives Analysis task below. 3.2.3. Alternatives Analysis: for up to three sites identified in the Alternatives Screening task above, identify advantages and disadvantages of each alternative and relative cost differences, including consideration of the following and other applicable differentiating factors: • Parking and access for City operations personnel and equipment • Impact on park access, public use and use of space thereafter not usable by park • Distance of additional gravity sewer construction necessary, including accommodation of Port of Everett pier sewer force main discharge • Depth of wet well • Distance to 480V power supply • Distance from standby generator to residential property • Bioxide®tank and standby generator location • Bioxide® supply modifications necessary • Construction/coordination conflicts with park or bridge projects Each consideration will be scored numerically to represent least to most favorable condition and each consideration may be weighted to allow prioritized criteria for the relative scoring. 3.3.Power, Controls and SCADA Integration: Identify primary elements of custom pump station power and control equipment including primary, and redundant elements where appropriate, including systems for level monitoring, pump control, Bioxide® supply, standby power, sensors and alarms and supporting features. CHS Engineers, LLC Page 3 of 5