Basement Backups and Flooding. Is Anyone Really in Control?

Transcription

1 Basement Backups and Flooding Is Anyone Really in Control?

2 Flood of June 19, 2009 Between 3.8 and 4.8 inches of rain in 3 hours Some areas reported more Second 100-year storm in as many years Statistically this is rare, about 1 in 10,000 Isn t t this exceedingly unlikely? Each year there is a 1 percent chance of this large of a storm occurring Odds of winning Powerball 1 in 195 million

3 100-Year Storm 7 6 Depth (inches) Time (hours)

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6 Impacts from Flood of June 19, 2009 Over 250 complaints to City Highway crews came in to address flash flooding of roads and intersections Sewer crews came in to prevent basement backups where possible and operate plant City staff responded to each complaint Site visit Phone call

7 Impacts from Flood of June 19, 2009 Camelot Forest subdivision had many streets closed because of flooding Fox River overtopped its banks River Road was closed Barker Road was closed Kinsey Park pond overflowed Detention ponds under construction at Brookfield Central High School overflowed

8 Top of the Sub-Continental Divide Two ponds overflowing at BCHS Not in low-lying lying areas Literally at the top of the sub-continental divide Not much flows into them, compared to other ponds in the City Shows just how severe and intense this rainstorm was

9 Impacts from Flood of June 19, 2009 Hundreds of homes all over the City without power for up to 14 hours in some areas Caused sump pumps to overflow into the sewer 43 sewer backups reported Treatment plant peaked at 60 MGD Normal plant flow is 8 MGD Peak design flow at plant is 50 MGD Treatment plant staff operated plant well

10 How does this Compare with the Storm of June 7-8, 2008? Different Less total rainfall in 2009 Rain came much faster in 2009 Storm occurred during middle of the night Full extent of flooding is not known Power outages were more scattered in 2009 Power outages were for longer durations in 2009

11 What is City Doing About this? Reviewed the City-Wide Flood Task Force recommendations Reconfirmed that the current standards for stormwater management and flood control are appropriate Staff is reviewing each complaint area and prioritizing responses Will need more study in some areas

12 What is City Doing About this? Continuing to implement stormwater improvement projects as identified in plans Continuing to implement sanitary sewer improvements Repairing leaking sewers and manholes Upsizing sewers where we can Working with WE Energies for reliable power Educating the public about this issue

13 Is Anyone in Control of Basement Backups and Flooding? Four categories of control What the City can control What a property owner can control What other agencies control What nature controls (i.e. Act of God) All four need to work in cooperation with one another in order for the system to work properly Failure of one or more of the four above may result in basement backups and flooding

14 What Does the City Control? Capacity of the storm water drainage system Capacity of the sanitary sewer system Maintenance of the storm water drainage system Maintenance of the sanitary sewer system Land development in the area

15 What Does the City Control? Capacity of the storm water drainage system Storm sewers and ditches are designed to convey approximately 3.8 inches of rain in a 24 hour period Water runoff from rains in excess of this standard or falling at a higher rainfall intensity will overload the sewers and ditches This excess water is designed to flow in streets, side yard swales and back yard swales street and yard flooding is not a failure of the system - better here than in your house

16 What Does the City Control? Capacity of the sanitary sewers Sanitary sewers are designed to convey wastewater, not rainwater, from properties Sanitary sewers are designed to convey a certain amount of leakage of clear water into the system Sanitary sewers are designed to convey not only the flow from current development, but also from future development that would be tributary to the sewer

17 What Does the City Control? Maintenance of the storm water drainage system The City routinely maintains the storm water drainage system including: re-ditch when needed repair or replace storm sewers and inlets when deteriorated upgrade the capacity of the system when required clear debris from inlets and grates to maintain flow into the system

18 What Does the City Control? Maintenance of the sanitary sewer system cleaning sewers regularly finding leaks in the system and repairing them replacing sanitary sewers and manholes when deteriorated upgrading the capacity of the system when required providing power to pump stations during power outages

19 What Does the City Control? Land development in the area Land use and zoning restricts development to certain development patterns, restricting the type of use and size of lot coverage Stormwater management ordinance restricts amount of runoff from a property to existing flow rates after development Certain uses are required to install grease traps to keep grease out of the sewers

20 What Can a Property Owner Control? Check drainage around the structure Keep drainage and sewer easements clear Ensure sump pump works when needed Keep clear water out of the sanitary sewer Take steps to protect against basement backups

21 What Can a Property Owner Control? Check drainage around the structure Make sure yard is graded away from house Slope all pavement away from the house (mudjack or replace if needed) Add clay fill around foundation of house to fill in areas that have settled slope away from house Raise window wells and consider installing window well covers Clean gutters regularly and extend downspouts and sump pump discharge line away from the house

22 What Can a Property Owner Control? Keep drainage and sewer easements clear Remove sheds, fences, retaining walls, & structures in drainage easements Remove lumber piles, firewood or mulch in drainage areas since they t float and then plug inlets and sewers Remove trees that obstruct flow of water or access to storm sewers Fences, sheds, play structures and fire pits encroaching into storm and sanitary sewer easements (Also note significant trees in easement)

23 What Can a Property Owner Control? Ensure sump pump works when needed Make sure sump pump is sized properly Make sure pump discharge line is sized properly and discharges overland instead of into a storm sewer Properly size circuit breakers and fuses to handle the size of the sump pump Check sump pump operation regularly Consider a battery backup for power outages Keep a spare sump pump on hand in case of failure

24 What Can a Property Owner Control? Keep clear water out of the sanitary sewer Do not route sump pump discharge into a laundry tub, floor drain or anything else that drains to the sanitary sewer Do not bail sump crock into floor drain or laundry tub or toilet or sink it causes basement backups Pump excess water out the basement window or haul in buckets up stairs and toss outdoors

25 What Can a Property Owner Control? Take steps to protect against basement backups Add a water sensing alarm to your basement that detects water on the floor and sounds an alarm Consider installing a backwater valve in your floor drain or sewer lateral Consider hung plumbing in the basement with a sealed crock for basement fixtures and floor drain Remove leaks and roots from sewer lateral (this is the pipe from your house to the main in the street)

26 What Do Other Agencies Control? WE Energies Provides electric power Maintains power lines Trims trees in conflict with power lines Restores power when lost during an emergency Their service is critical to ensure sump pumps operate during major rain events

27 What Do Other Agencies Control? News agencies Weathermen predict rain events with varying degrees of accuracy Properly forecasted storms provide staff time to prepare in advance, minimizing response time Unpredicted storms and storms that are more severe than predicted take longer to respond to

28 What Does Nature Control? Intensity of rainfall Total rainfall amount When the storm hits How long it rains Where in the City it rains How widespread the storm is Whether the storm was predictable or not

29 What Does Nature Control? Lightning can cause power outages Wind speed can blow down trees causing power outages Saturated soils prior to the rain increases runoff Frozen ground during the rainfall event increases runoff Snow cover when the rain falls increases runoff

30 Should the City Initiate Control over Private Sector Sources? The City could consider inspecting private property for sources of clear water Illegally connected downspouts and sump pumps Legally connected combination sumps (includes foundation drains and floor drain/laundry tub) Could start a pilot program focusing on structures constructed prior to 1954 Prior to 1954 plumbing code allowed foundation drains into the sanitary sewer

31 Is Anyone Really in Control? Yes No Depends on what aspect of the storm you consider We all must do our part to minimize the frequency and severity of flooding and basement backups in Brookfield Working together benefits everyone