25I - AGMT - OCWD ASSESSMENT - Laserfiche WebLink

Home Browse Search

CITY OF SANTA ANA Well No. 32 Nitrate Mitigation and Rehabilitation Study INTRODUCTION The City of Santa Ana pumps water from the groundwater basin from Well Nos, 16, 18, 20, 21, 24, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 and 41. Import water is also obtained from several Metropolitan Water District (MWD) connections. Some of the City's wells produce groundwater with elevated nitrate levels, including Well No. 32. The City has developed a Nitrate Blending Plan and mixes the high nitrate ground water with the low nitrate groundwater at the reservoir. Per the Nitrate Blending Plan the City reports the results of weekly and quarterly monitoring to the Department of Public Health comparing the nitrate level from each of the wells as well as the nitrate level leaving the City's Walnut and Garthe reservoirs. Well No. 32 has been inactive for the past five to six years due to low operating efficiencies and high nitrate levels. The purpose of the project is to review the nitrate levels that are present at Well No. 32 and evaluate alternatives for either treatment or blending of the water into the City's distribution system. The space requirements and site constraints are also considerations. An estimate of probable construction and operation costs will be prepared for the project alternatives in order to determine the best value project for the City. The recommended project will also include the goals of minimizing chemical usage and/or waste discharge and selecting processes that are easy to operate and maintain for the City staff. The following alternatives are considered in the study: 1) no action, 2) blending in the distribution system at the following locations: Garthe Reservoir, Memory Lane Pressure Reducing Facility (blending Well No. 32 water into the well water from the City's easterly sources), or 3) utilizing treatment technologies to reduce the nitrate levels located either on -site at Morrison Park or at Garthe Reservoir. In addition to the nitrate mitigation, the study also includes the following: cost estimate for rehabilitation of the well, conceptual plan and cost for removing the existing vault and constructing a building over the well to improve access and replacing the existing MCC cabinet (that has been previously flooded). 1.1 Scope of Work The project scope of work includes the following key tasks 1. Review of the City's Nitrate Blending Plan, available water quality data from the City for Well No. 32, Memory Lane Pressure Reducing Facility and Garthe Reservoir as well as the reports submitted to the Department of Public Health. 2. Review of the construction as- builts for Well No. 32, the Memory Lane Pressure Reducing Facility and Garthe Reservoir, as well as, the latest street improvement, water and/or sewer plans for Bristol Street, Westwood Avenue and Memory Lane (to determine if there is an available utility corridor for a new pipeline). 3. Review of the Well Report of the completion of the well and history of the groundwater soundings taken by the City for Well No. 32. P.T0059T0086V gin etingA05\ Well -32- Nitrate- Mi[igatlonU raft ReportV02teztdo251 —1 � TETRA TECH