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More specifically forth is proposal the City is seeking submittal of qualifications for two options. Design and construction support services for: 04'1I;)N A: YV/a'IE.I Rf:SOUI`iE:3 • Rehabilitation of a 30 year old water well ■ 1500 LF of domestic water design (12" PVC) 600 LF of sewer design (15" Material TBD) with arterial street PRELIMINARY ANALYSIS: 1. 5ewerMateriai: Many factors should be considered when determining the best material for sewer construction. These include: » Corrosion » Weight » Abrasion » Imperviousness » Strength » Cost » Durability » Hydraulic Efficiency Of the many materials available each offers a set of unique advantages and disadvantages. For a 15" pipe, the material most commonly used in local cities under an arterial roadway would be vitrified clay pipe (VGP). It performs well in typical urban loading conditions and maintenance departments are well prepared to work with it. Our experience would have us assume UCP will be high on the list of options. 2, The City has determined that the existing water well performance dropped by 35%. This percent is above the 25% rule of thumb that would indicate it's time for rehabilitation. The RFP mentions that the water well is a sand producers but does not indicate if the sand production has increased. It is our assumption that the City has concluded that the sand production rate is within an acceptable range and that the Information is meant to determine that the aquifer type is "Sandstone," The most prevalent water well problems for this type of aquifer would be: -FISSURE PLUGGING - CASING FAILURE - SAND PRODUCTION - CORROSION The anticipated maintenance frequency for a sandstone aquifer would average 8 years. If the well has dropped 35% over 15 years this Is within the anticipated limits and sand production has not Increased, casing failure is unlikely. It is also our assumption that surface equipment has been evaluated and that the well was constructed with corrosion in mind. This leaves plugging as the likely cause for loss of production! We anticipate that further evaluation will lead to the following rehabilitation methods: A. Aqua Freed CO2 Injection: Effective at removing mineral incrustation, biological fouling, and physical plugging. Provides extensive geological penetration, it is 100% green, and environmentally sound with no adverse chemical waste stream. B. Chemical and Acid Cleaning: Used in Conjunction with pumping and surging it Is effective at dissolving minerals and impacting biological activity and physical plugging of sands. The chemical solution is tailored specifically for the plugging problem. It offers limited geological formation penetration and produces a waste stream of spent chemicals that must be neutralized and disposed of properly. 0!1T101V1 Ci: CaENER'AI- FNC,INEER11,1G (01HF.R THAN WA F, R Fk,175' lii;C'F_ • Conceptual street widening and rehabilitation including parkway improvements lo New bike lane Intersections are complete PRELIMINARY ANALYSIS: J. Exclusions » Traffic signals and median design » Traffic Report )) Right -of -Way Services 2. Assumptions » Water, sewer, and dry utilities will be protected in place » Manholes and valves will be adjusted to grade » Storm drain will require retrofit to new curb and gutter alignment » Street lights and illumination design required » Must meet water quality requirements » Sound wall required HLATfOAMS City of Santa Ana Civil Engineering Services: RFP 11-083 6