Chapter 8: Water Supply & Sanitary Systems

Transcription

1 Chapter 8: Water Supply & Sanitary Systems Manage, Treat & Reserve Comprehensive Plan 2040

2 2 8. WATER SUPPLY & SANITARY SYSTEM

3 INTRODUCTION This chapter of the City of Lauderdale s 2040 Comprehensive Plan addresses water supply and wastewater (sanitary sewer) systems in the City. It is consistent with the Metropolitan Council s Thrive MSP 2040 planning and 2040 Water Resources Policy Plan. This Plan chapter is primarily intended to assist the Metropolitan Council Environmental Services (MCES) with continued operation of the Metropolitan Disposal System (MDS) for wastewater collection and treatment Water Supply & Sanitary Highlights What s to Come»» The St. Paul Regional Water Service supplies the City with clean water.»» Sanitary Sewer services in the City are part of the regional system. Capacity is adequate for existing and forecasted projections through WATER SUPPLY & SANITARY SYSTEMS

4 WATER SUPPLY PLAN Since the late 1990s, St. Paul Regional Water Service (SPRWS) has owned and maintained the water supply utilities in the City of Lauderdale. As the City does not manage its own water supply, a local water supply plan is not required as part of the 2040 Comprehensive Plan. More information about the local water supply plan for the St. Paul Regional Water Service can be found online at Water Sources and Conservation This source water comes from the Mississippi River and the surrounding watershed. SPRWS also maintains a series of groundwater wells pumping from the Prairie du Chien-Jordan aquifer as a backup supply system. intake station in Fridley, which is located roughly 25 miles northwest of the utility s water treatment plant 4 There are currently no private water supplies within the City, and protection of water supply sources for Lauderdale falls outside of local jurisdictional limits. Likely the best way residents and businesses within Lauderdale can contribute to conservation and protection of the local water supply is by encouraging local groundwater recharge. Adding opportunities for water runoff to infiltrate on or near local properties will reduce pollution and contamination and contribute to a more sustainable water supply for the region. Additionally, residents and businesses can work to conserve the water supply used by reducing water use. Implementing ideas like rain barrels, reduced lawn, and grey-water reuse all contribute to using less water from the municipal water supply. The City will continue to encourage water conservation by promoting education and conservation programs for residents. Special Well and Boring Construction Area The City of Lauderdale is within the MDH-designated Twin Cities Army Ammunition Plant (TCAAP) Special Well and Boring Construction Area (SWBCA) which went into effect July 1, 1996 and was most recently updated in April Groundwater in portions of the designated area has been contaminated with volatile organic compounds (VOCs) from solvents used and disposed at TCAAP in Arden Hills. The designation requires that construction, repair, and sealing of regulated wells and borings within the SWBCA only take place in accordance with the conditions and requirements set forth by the MDH. Efforts to contain and clean up the contamination at the TCAAP facility and to the south of TCAAP have been underway for many years through contaminated groundwater treatment 8. WATER SUPPLY & SANITARY SYSTEM

5 and removal of water-supply wells known to be contaminated. Additional concern centers around construction of new wells or borings or modification of existing wells or borings within the SWBCA that may interfere with cleanup efforts and/or cause further spread of the contamination. It is therefore important for the City of Lauderdale to implement and enforce the requirements of the SWBCA with respect to existing and proposed water supply wells in the area. Of particular significance to Lauderdale, any construction-related and environmental borings are required to follow these regulations. System Maintenance Many of the City s water lines were replaced during road reconstruction projects in the early 2000s. There are currently no plans by SPRWS to replace water mains in Lauderdale. However, the City is currently discussing the possibility of taking back a portion of Eustis Street, and if that were to occur, SPRWS will update the watermains in coordination with proposed road reconstruction project. WASTEWATER (SANITARY) SEWER SYSTEM System Capacity Description 5 Lauderdale s sewers were originally constructed in the 1950s, and the City completed a group of major reconstruction projects in 2003 to replace and update the streets, sewers, and waterlines. Since the adoption of the 2030 Plan in 2010 the City has been using cured in place pipe (CIPP) to rehabilitate and repair the existing sewer lines that were not updated during the major street reconstruction projects. The City of Lauderdale is served by regional sanitary sewer service. Lauderdale s sanitary sewer system is shown on Map 8-1. The system is divided into five sanitary sewer district defined by points of discharge to sewer trunk lines. Districts 1 and 2 flow to MCES Meter M103, located near 33rd Avenue Southeast and Talmadge Avenue in Minneapolis. Meter M103 and Lauderdale Districts 3 and 4 all flow to MCES Interceptor 1-MN- 301 near 33rd Avenue Southeast and Como Avenue in Minneapolis. District 5 flows to St. Paul s sewer system at the intersection of Fulham Street and Hoyt Avenue. Lauderdale does not have a wastewater treatment facility. Wastewater is collected in the City sewer system and discharged to the systems described above; which convey wastewater to the MCES treatment plant at Pig s Eye Lake in St. Paul. MCES charges Lauderdale for treatment of this wastewater. Districts 3, 4, and 5 are periodically metered by the MCES. 8. WATER SUPPLY & SANITARY SYSTEMS

6 Map 8-1 Sanitary Sewer System Map MCES Meter Inter-community Connection 6 Source: City of Lauderdale 8. WATER SUPPLY & SANITARY SYSTEM

7 System Features Lauderdale s sanitary sewer system is composed of approximately 6.7 miles of sewer lines and 156 manholes. There are no lift stations in the system. Most of the sanitary sewers in Lauderdale were replaced between 2000 and 2003, and those not replaced have been lined since The City redirected flows in District 1 to the north and constructed a trunk line parallel to Highway 280 to carry this flow south. These improvements allowed Lauderdale to abandon four aging lift stations. There are no on-site septic systems or large sewer users (flow exceeding 0.05 MGD) located within the City. Undeveloped parcels in Lauderdale can be adequately served using existing facilities, so there are no system extensions or new MDS connection points planned. Future improvements will focus on maintenance of the existing system. Projected Population and Wastewater Flows Table 8-1 lists the population, households and employment as estimated by the City of Lauderdale in Chapter 3 of this Plan, and identifies and wastewater flow projections issued by the Metropolitan Council in the City of Lauderdale s 2015 System Statement. 7 Table 8-1 Lauderdale Wastewater Flow Projections Population 2,490 2,704 3,007 Households 1,260 1,364 1,519 Employment 890 1,025 1,161 Average Wastewater Flow Allowable Peak Flow Source: Metropolitan Council (Peak Flow Factor = 3.9), City of Lauderdale, SHC System Flows and Capacity System flows have been estimated for current (2018) conditions as well as 2040 projected land use conditions. The average wastewater flow from each sanitary sewer district has been estimated by applying unit flow rates to each land use category. These estimates are summarized in Tables 8-2 and 8-3. The sanitary sewer system must be capable of handling the anticipated peak flows, estimated by applying a peak flow factor to the average flow. The peak flow factor accounts for flow variability and includes an allowance for infiltration and inflow. 8. WATER SUPPLY & SANITARY SYSTEMS

8 Table 8-2. Wastewater System Capacity - Existing 8 Wastewater Flow and System Capacity - Existing Apartments Commercial Industrial Institutional Townhome/ Condo Single Family Residential Utility Open Space Railway ROW Roadway ROW Park & Recreation Total Existing 2018 Landuse Area (Acres) Sewer District City Total Units per acre Persons per unit Population Gallons/person/day Gallons/acre/day MGD / acre MGD / City Average Flow Sewer District City Total Capacity/ Design Capactiy slope (ft/ft) Trunk dia (in) Design Flow (MDG) Peak Factor Avg Flow Sewer District Subtotal to M Subtotal to 1-MN MN City Total WATER SUPPLY & SANITARY SYSTEM

9 Table 8-3. Wastewater System Capacity Wastewater Flow and System Capacity Mixed Use Business Park Industrial High Density Residential Medium Density Residential Low Density Resdiential Roadway Railway Park, Recreation & Open Space Total Planned 2040 Land Use Area (Acres) Sewer District City Total Units per acre Persons per unit Population Gallons/person/day Gallons/acre/day MGD / acre MGD / City Average Flow Sewer District City Total Capacity/ Design Capactiy slope (ft/ft) Trunk dia (in) Design Flow (MDG) Peak Factor Avg Flow Sewer District Subtotal to M Subtotal to 1-MN MN City Total WATER SUPPLY & SANITARY SYSTEMS

10 Trunk line capacities are also included in Tables 8-2 and 8-3. The existing trunk system has adequate capacity for existing and estimated flows. Table 8-4 applies forecasted wastewater flows by proposed land use for 10-year increments, identifying residential and commercial flows for the system. All total wastewater flows are within the projected averages and well within peak flow capacity. Table 8-4. Lauderdale Sanitary Sewer Forecasts by Metered Area Households Est. Units / Jobs Avg Flow Est. Units / Jobs Avg Flow Est. Units / Jobs Avg Flow M103 1, , , Unmetered - St. Paul Unmetered - Mpls TOTAL 1, , , Employment M Unmetered - St. Paul Unmetered - Mpls TOTAL , , Total Wastewater Flow Source: Metropolitan Council, City of Lauderdale, Stantec, SHC *Land use designation changes between 2020 and 2040 may account or differing acreages and resulting average flows by use type. Inflow and Infiltration Inflow and Infiltration (I/I) can come from several sources contributing non-sanitary flow into the sanitary sewer system. Example sources include surface runoff from roofs and manholes drainage from draintile and sump pumps, and leaks from failing sanitary infrastructure. The Metropolitan Council establishes I/I goals in the 2040 Water Resources Policy Plan for all communities discharging wastewater to the Metropolitan Disposal System (MDS). Communities identified to have excessive I/I in their sanitary sewer systems are required to reduce and eliminate the excess. Lauderdale has previously been identified as a community with excess I/I. Lauderdale s I/I Reduction Efforts In January 2007, the City of Lauderdale initiated a multifaceted Inflow and Infiltration 8. WATER SUPPLY & SANITARY SYSTEM

11 reduction program. Initially, the City smoke tested the City and identified a significant source of inflow and infiltration at an industrial business. This issue was corrected and the City was exempted from the I/I program until another exceedance occurred. After MCES changed its metering thresholds, the City had exceedances that became the impetus for on-going efforts to address I/I. Some of the easiest fixes included closing sewer pick holes and rehabilitating leaky manholes. The City also worked closely with another industrial business to redirect its stormwater runoff from the building to surface water and storm sewer features eliminating the conveyance of the building s runoff into the sanitary sewer system. The replumbing of their building was completed in 2016 to accomplish this effort. Concurrently to working with the industrial businesses, the City undertook a flow metering study to determine which portions of the City contributed to I/I exceedance. With grant assistance from the Metropolitan Council, the City has also been able to line the sanitary sewer pipes that were not completed as part of a roadway project. In 2018, the City will be filling in gaps where pipes have not been replaced north of Larpenteur. Once the project is complete, the City will have only one more project remaining to finish the replacement or lining of the entire system. The City also continually looks for sump pumps draining to the sanitary sewer system as part of the City s building permit and rental housing inspections programs. 11 Goals for I/I Management Lauderdale will continue its efforts to eliminate excess I/I with the following goals for system management: Replace sewer linings Repair cracks and joints in public system Monitor sump pump drainage Educate property owners about reducing I/I Implement residential monitoring program for private sewer line maintenance Lauderdale will also work cooperatively with other agencies and property owners to educate residents and businesses about the importance of reducing I/I and promote ongoing maintenance of infrastructure on private property. It is particularly important to inspect and repair damaged sewer service lines connected to the MDS, and replace older clay pipes that are beyond their useful life. 8. WATER SUPPLY & SANITARY SYSTEMS

12 Policies and Regulations Lauderdale regulates against inflow and infiltration to the sanitary system from surface water sources. City Ordinance : Discharge of Surface Water Prohibited states Except as otherwise expressly authorized in this subdivision, no water from any roof, surface, sump pump, footing tile or drains, swimming pool, any other natural precipitation or groundwater, cooling water, or industrial process shall be discharged into the sanitary sewer system. Dwellings and other buildings and structures which require, because of the infiltration of water into basements, crawl spaces and the like, a sump pump discharge system shall have a permanently installed discharge line which shall not at any time discharge water into the sanitary sewer system. The ordinance also requires disconnection of any roof, surface, sump pump, footing tile or drains, swimming pool, cooling water or unpolluted industrial process water now connected and/or discharging into the sanitary sewer system shall disconnect or remove the same. The City will continue to monitor compliance with this ordinance through its permitting processes WATER SUPPLY & SANITARY SYSTEM