Item 17 - Agreement with David Evans and Associates, Inc. for Landscape (10th and Flower Park)

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Proposal to provide Landscape Architectural Design Services for loth and Flower Park — RFP No. 22-124 boring. The pipe will be secured in the borehole and pea gravel filter pack will be poured down the borehole to surround the pipe casing and hole bottom. Water will be added to the borehole until the water level is as near the ground surface as can be achieved and allowed to pre-soak Pre -Soaking: Pre-soaking will be done by inundating the borehole with water for at least one hour. Test Procedure: After presoak, the borehole will be filled with water to 12 inches above the bottom and the drop in water level in the borehole shall be observed. The following 2 conditions are utilized to determine the time interval between readings. ■ If water remains in the hole after 10 minutes but drains before 30 minutes, the time interval between readings shall be 10 minutes. ■ If water remains in the hole after 30 minutes, the time interval between readings shall be 30 minutes. After completion of presoak, the borehole shall be inundated to a level less than or equal to the presoak depth. For each successive infiltration test reading, the starting water level must be at this initial water depth. A sounder shall be utilized to determine the water level during each test. All measurements of water level shall be taken to the nearest 1/8-inch increment. Infiltration test readings shall be conducted a minimum of eight times, or when a stabilized rate of drop has been obtained, whichever occurs first. A stabilized rate is defined as when the highest and lowest readings of three consecutive infiltration tests are within 10 percent of each other. The average of the stabilized rate over the last 3 consecutive test readings shall be used as the pre - adjusted infiltration rate. Attempts will be made to remove the pipe from the borings. If the attempts fail, the pipe will be abandoned in place and the hole backfilled with soil cuttings Laboratory Testing: Laboratory testing will include, but may not be limited to; In -situ moisture and dry density; Soils corrosivity; R-value; Collapse; Expansion Index; Sieve analysis; Maximum density; and Direct shear. Engineering Analyses and Report Preparation: Data obtained from the exploratory borings and the laboratory testing program will be evaluated. Engineering analyses will be performed to develop design and construction recommendations that will be presented in a geotechnical investigation report. 1.2 — Horizontal Control Plans DEA will prepare a 1 " = 20'scale horizontal and vertical control plan for the project depicting a survey control line and dimensions to pertinent site features for use in the layout of the park and site features during construction. Deliverables: 1 " = 20'scale horizontal and vertical control plan. L3 - Grading and Drainage Plan DEA will prepare a 1 "= 20' scale precise grading, drainage and paving plan for the project depicting grading contours, slopes, finish surface elevations, drainage patterns, swales, typical cross sections, details and proposed civil related improvements including pavement, hardscape flatwork and access ramps. The plan will consider ADA requirements for accessibility. Deliverables: 1" = 20'scale grading and drainage plan. L4 — Composite Storm Drain and Water Plan DEA will prepare a 1 "= 20'scale composite storm drain and water plan for the project depicting proposed storm drain and domestic water pipe alignments and structures required to service the project site. Deliverables: 1" = 20'scale composite storm drain and domestic water plan. L5 - Erosion Control Plan This plan will include the preparation of erosion control measures for use in construction to reduce sediment transport within the site. Deliverables: 1 " = 20' erosion control plan as noted above. 1.6 - Final WQMP DEA will prepare finalize the conceptual WQMP. Deliverables: Finalized WQMP. David Evans and Associates, Inc. I February 28, 2023 1 11