Saving Time, Money With Sanitary Sewer Pipe Lining A Message fromCity Engineer Rob Phillips

I recently celebrated my 50th birthday, which, per the nature of most major life landmarks, has lent well to reflection on where I have been and where I would like to be. Within the realm of my career, much has changed since I first started work with the City over two decades ago. The basic principles have remained true, but, as one would imagine, the focus of our attention has seen notable shifts. With the snow melting once again, our attitude toward stormwater seems especially relevant. When I started with the City of Madison in the late 1980’s, the emphasis was on controlling the rate that we release stormwater and how increases in impervious areas from development affects the small streams that drained the developing areas. Today, the emphasis is on both the quantity and the quality of stormwater runoff. Many are not aware, but Madison and Dane County are ahead of other areas in the state and well ahead of most areas of the country when it comes to handling stormwater. But, of course, we aren’t anywhere close to where we want to be and we have a great deal yet to accomplish. Looking ahead, how will technology help us in the future? New and innovative ideas are everywhere, but many are not yet practical and the benefits can be exaggerated. Still, we have to be willing to consider them; we have to take the time to do thorough research and we have to be willing to risk trying something new if we find an idea that has promise. The treatment of stormwater with alum to remove phosphorous is one technology with particular promise. This is not a new technology; however, it is to the Madison area. This technology has the potential to remove significant amounts of nutrients at a far lower cost than traditional urban storm water practices. Alum treatment of storm water and even possibly lake water has the potential to make a discernable difference in our water quality. Alum is just one example of a technology that may be able to help improve water quality. The future holds an infinite supply of new ideas just waiting to be considered.

Madison Water Wayswww.cityofmadison.com/engineering/stormwater News from your Stormwater Utility

spring 2013

City Engineering will test the effectiveness of using Aluminum Sulfate (alum) in an urban stormwater pond as one means to reduce our discharge of phosphorus to meet EPA/DNR mandates for the Rock River Watershed. Glenway Pond is a stormwater detention pond lo-cated on UW-Arboretum property and receives runoff from a 230-acre watershed. Stormwater enters the pond through a large storm structure along Monroe Street and discharges to Lake Wingra. Liquid alum will be pumped into the stormwater based on the flow rate in the incom-ing pipe. The Alum generates a “floc” or larger particle that binds and removes phosphorus and other nutrients from the water column. To determine alum’s effectiveness, various measure-ments will be taken for the incoming and outgoing stormwater. Most pollutants including sol-ids, bacteria and heavy metals will be retained within the pond so downstream concentrations, and hence discharge to Lake Wingra of these contaminants, are expected to decrease. The City of Madison plans to conduct the demonstration of alum treatment for a two year period.

Alum Treatment Demonstration Project

Infiltration and inflow (I&I) into sanitary sewer pipes from stormwater is a problem with sani-tary sewer pipes that are not water-tight, causing issues with capacity and treatment of typical stormwater pollutants such as chloride. Both municipalites and treatment plants are concerned about minimizing I&I. Until about 1980, sanitary pipes were short lengths of clay pipes laid end-to-end, which allowed seepage into and out of the pipes and were prone to cracking, breaking, and tree roots. Identifying I&I issues can be done with in-pipe video inspections, flow monitor-ing, or smoke tests.

While new pipes are typically made of PVC, Cured-In-Place Pipe (CIPP) lining is a newer tech-nique to repair pipes that costs significantly less than an open cut pipe replacement and takes a fraction of the time. CIPP utilizes a seamless, resin-saturated felt tube that is inserted into an existing pipe. After the CIPP liner is in place, the tube is inflated and is heated up using steam in order to harden the liner to its final shape. After the liner is hardened, a robotic cutter is used to restore service to individual buildings. Typically, from start to finish, the process takes ap-proximately five hours and since the process uses existing manholes to gain access into the sewer system, there is no excavation needed to make repairs. CIPP allows for fewer disturbances to the general public, while creating a new pipe that prevents I&I and tree root infiltration into sanitary sewer pipes. The liners are custom made to fit the length and diameter of the pipe that is to be repaired. If the CIPP liner is designed and installed correctly, the design life of the pipe is 50 years or more.

Not to scaleAdapted from NASSCO CIPP Committee, . Inspector Training and Certi�cation Program. NASSCO, 2008

Existing Pipe

Boiler Truck

Leak

CIPP

Circulation Pump

City Greenways

Lake Mendota

L. Wingra

City GreenwaysGreenways are part of the City of Madison’s stormwater conveyance sys-tem. Th ese grassy areas are designed to slow down stormwater and pro-vide some level of treatment by helping to remove sediment and nutri-ents. In order to maintain these areas for their intended purpose, they are generally mowed twice per year to minimize invasive weeds and volun-teer trees. Trees in a greenway lead to erosion issues when they shade out lower growing vegetation, exposing bare ground.

Private use of these public areas is regulated by city ordinance. Generally, only temporary uses are allowed, such as walking or other non-destruc-tive recreational activities (e.g., Frisbee). Th ey are not intended to be ex-tensions of personal yards: no trampolines, play structures, vegetable gar-dens, trees, or disposal of yard waste. Stormwater needs to be able to run freely and our crews need to be able to safely mow these areas. Encroach-ments and other non-compliance uses will be ordered to be removed.

Th e City’s standard mowing pofi rst mowing cycle occurs betweretention ponds . Th is buff er is Conservation to determine whmow these areas between May completed, weather permitt ing. close to the water’s edge as is saf

Eroding greenway bank Recently reconstructed greenway

Greenway in autumn

Greenways with severely eroded banks (below) are prime candidates for a makeover (be-low, right). We save tons of sediment from depositing into downstream waterways with each greenway im-provement project.

Lake Monona

Lake Waubesa

Greenway Uses

WalkingVegetable gardens

Bird watching

Above-ground pools

Dog kennels

Planting shrubs

Frisbee game

Play structure

Yard waste dump site

Th e City’s greenway mowing policy is de-signed to ensure that the City’s greenways and ponds perform the function for which they were designed – stormwater drainage and conveyance that improves our water quality while minimizing the potential for fl ooding. In addition to reducing the height of vegeta-tion, mowing is used to prevent woody plants from establishing. Woody plants can quickly overtake a prairie area and crowd out lower height vegetation resulting in erosion and pools of standing water that promote mosqui-to breeding. Additionally, mowing helps con-trol noxious weeds and the spread of invasive vegetation. We do not mow these areas more frequently because native grasses and prairie plants are valuable in reducing the amount of urban runoff that reached our lakes and riv-ers and they provide local habitat to birds and other critt ers. Th ese plants promote in-fi ltration of stormwater into the ground while providing a buff er that captures a signifi cant amount of sediment, nutrients and other pol-lutants before they reach surface waters.In 2012, the City entered Year 2 of a 3-year pilot program to reduce mowing frequen-cies in ten greenway areas. Th is pilot program has been led by Si Widstrand, retired City of Madison Parks Development Manager, and is designed to restore native prairie plants and grasses in these areas. Th e program includes spot mowing, string trimming and manual cutt ing and chemical treatment of woody, invasive and noxious spe-cies. While 2012 saw a s i g n i f i c a n t increase in chemical treat-ments in these areas, we be-lieve this is a short‐term necessity for e l i m i n a t i n g these undesir-able species. Over time, as more desirable prairie plant and grasses become more established less chemi-cal treatment will be required.

r g

“For me, the lesson learned fr om this work is that we can accomplish a great deal with limited hours and limited herbicides if they are specifi -cally targeted to control in-vasive species and unwanted woody plants. And that may allow us to reduce (not eliminate) mowing, increase wildlife habitat, improve aesthetics, etc.”-Si Widstrand, former City Parks Conservation Manager

Pilot Greenway Maintenance Project

olicy provides for mowing each greenway and pond area 2 times per year. Th e een April 15th and October 15th and leaves a 10’ to 15’ un-mowed buff er around to make them less att ractive to Canada Geese. Engineering consults with Parks

hich greenways/ponds provide suitable song-bird nesting habitat and does not 15th and July 15th. Th e second cycle begins in midOctober and continues until During this cycle ponds are mowed as

fely possible.

Greenway with a concrete cunett e

City Engineering

� is program began in 2005 as a pilot project along three blocks of Ad-ams Street. � e rain gardens are designed to accept stormwater runo� from dirty streets. � e native plants in the garden help reduce the amount of nutrients in the runo� and the special soil mix reduces the heavy metals and other urban pollutants. In� ltration and evapotranspiration from the plants reduces the amount of water running into the storm sewer system. Groundwater is recharged through in� ltration encouraging a more natural water cycle.City Engineering reviews each street reconstruction and resurfacing proj-ect for suitability of terrace rain gardens. If the terraces are wide enough, the area isn’t too steep, and there is enough space between trees, homeown-ers are given the opportunity to participate. We will only install rain gar-dens where they will be cared for, and so request $400 cost share from the homeowner. � is amounts to less than 25% of the total cost to the City to construct and plant the gardens. At the end of 2012, we have installed over 80 terrace rain gardens.Homeowners can also install rain gardens on their property, though there is no cost share available. For more information:www.cityofmadison.com/engineering/stormwater/raingardens

Type of Facility: Stormwater TreatmentWhere: Multiple locations

Contact: Stormwater Division Genesis Steinhorst gsteinhorst@cityofmadison.com

Cost: $1600 per rain garden (approx)Cost Per Unit: $1200 (homeowner pays $400)Cost varies by project, contractor

Annual Maintenance Cost: $0Homeowner responsible for all maintenance.

Sustainability MeasuresTerrace Rain Garden Program

Details

Fox Ave Rain Garden, 2011

Fox Ave Rain Garden, 2009

Adams Street Rain Garden, 2006

Adams Street Rain Garden, 2009

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City Engineering ContactsMain Office · (608) 266-4751Erosion Control · 267-1199Stormwater Utility Billing · 267-1199Sidewalk Concerns · 266-4537Sewer Maintenance · 266-4430

Look for future issues of Water Ways for additional City Engineering Sustainability Measures, where we highlight projects that promote greener infrastructure practices.