Wednesday, August 18, 2010

Another sediment spill by Rawson at Old Middleton Rd

This site needed special attention to erosion control, because:
  • The site is steep.
  • It straddles a creek that coveys stormwater directly to Lake Mendota.
  • Considerable runoff enters the site from both ends of Old Middleton Rd.
Despite these obvious warning signs, the erosion control plan was mediocre and poorly implemented.

Ponds still filled

The unfinished sediment ponds remain partially filled, due to previous neglect in allowing them to fill while under construction.  The presence of water in the ponds is probably going to delay completion, and some damage has occurred.

Since my earlier comments on this, runoff from Old Middleton Rd into the ponds has been mostly blocked by a gravel dike.

Silt fences failed again, sediment spill into creek

Silt fences guarding both sides of the creek failed.

The first failure occurred because the stakes holding the fence were too small.  Where the fence failed the first time, larger stakes were added, but not all the stakes were upgraded.  So when another storm hit, the fence failed again where the smaller stakes remained.  The lesson--"stakes too small"--wasn't learned the first time.

The erosion control plan states: "Do not disturb existing channel between ponds."  Yet due to the failure of stilt fences on at least two occasions, two gravel dams were recently placed in the creek itself.  The fence itself hasn't been repaired, at least several days after the storm.

There's a delta of sediment in the creek where the south fence failed. 

Below the gravel dams in the creek, you can see small patches of sediment, showing the gravel dams in the creek didn't prevent sediment from moving downstream towards Lake Mendota.

The arrangement of gravel dam, rock dam, and silt fence on the south side of the creek was illogical and ineffective, allowing water to easily bypass and dump sediment into the creek.
The whole approach to erosion control at this site has been ineffective, constantly closing the barn door with gravel dams after the horse has escaped.

An opportunity missed on the south side of the project

An erosion control checklist should include: "Survey the site to determine if runoff entering the site can be diverted around the site.  If it can't be diverted, determine if it can be conveyed through the site in pipes or channels, without eroding or picking up sediment."

If water entering the site is clean, then it can be dumped beyond the site--even into lakes or streams--if it is kept clean while passing through the site.

There's clean runoff coming from this block above the start of construction, on the S approach of Old Middleton Rd.

Here's where the runoff from the block above enters the site... lots coming in.

This runoff could be diverted to the NE onto Capitol Av.   Or, it could be conveyed through the site in a plastic pipe, and dumped into the creek, since it would be clean.  This diversion would relieve some of the strain on the erosion control measures closer to the creek. 

At the very least, this entering runoff could have been diverted down the west side of Old Middleton Rd, where the pavement is still intact. 

Instead, the incoming runoff was allowed to run down the east side of Old Middleton Rd, where the pavement was ripped up.  Hence, much more erosion occurred.

Additional problems reveal a sloppy approach

 In three places, the creek (right) is not protected from disturbed areas by any fence or silt sock.

 The gravel dams were breached in several places by tracks, making them ineffective.

This pile of dirt, in the middle of the runoff flow on the hill, should have been protected with silt socks.

Runoff and sediment is moving around  some of the gravel dams on the hill.

The bottom line: Lots of dirty runoff, like this filling one of the ponds, got into the creek.

Who is responsible for these continuing problems:

Design Engineer: Lisa Coleman, 266-4093, City Engineering, . No mention of the need to deflect runoff was made in the erosion control plan.

Construction Engineer: John Fahrney, City Engineering,

Contractor: Rawson Contractors (Low bid was $1, 399, 029.85), Kenneth Servi, President,

Permit authority: Tim Troester, (608) 267-1995,

Erosion Control Permittee: Signed by Robert Phillips, delegated to John Fahrney, City Engineering,(608) 266-9091,

Inspector on 7/23 who missed last chance to deflect inflow: Stewart Mael, (608) 261-9695,

Grantor of permit for construction of ponds: DNR Water Management Specialist Cami Peterson, 608-275-3208. No mention was made in the permit of the need to deflect runoff from the ponds under construction.
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Tuesday, August 17, 2010

Course on Construction Site Erosion Control

"Learn techniques to establish Stormwater Best Management Practices (BMPs) for your construction site, and eliminate problems before they cause higher costs and slowdowns for your project.
This practical seminar can help you and your project staff save time and money by avoiding erosion and sediment releases. You will learn about proper installation and maintenance of typical BMPs as well as proper documentation to help keep your project in compliance with local and state regulations.

This course is of benefit to inspectors, contractors, foremen, project managers, consultants, stormwater managers, and owners of construction site projects and related activities (grading, culvert replacements, utility trenching, etc.)"

Source, and more info...

Monday, August 16, 2010

Street sweeping--remarkably ineffective

Today as I walked along Caromar Dr, a Bobcat passed right next to me as it swept the street in front of the Sequoia Commons II construction site.

Street sweeping is required as far from the site as necessary, and by the end of the work day.  It's one of the six erosion control methods most frequently used in Madison.

I could see the sweeping was remarkably ineffective--there were tracks of dried mud still on the street where it had just passed.  I fixed my eyes on one large, dried clod as the Bobcat passed right next to me--the clod was still there after the Bobcat passed over it.

A 1996  EPA study also found street sweeping to be the least effective of the three methods studied for keeping muddy tracks from construction off streets

Besides failing to remove mud where sweeping occurs, the method has other shortcomings:
  • It creates dust, adding to air pollution
  • It simply spreads the dirt more widely around the street
  • Sweepers frequently miss the gutters--the most important area to sweep.  Any dirt there is washed directly to the lakes.
No contractor that relies on ineffective methods deserves a GREEN rating from this blog.

 I believe the City deserves the most responsibility for this failure, because they continue to rely on sweeping, rather than on more effective BMPs, such as tire washing at construction sites.

The Parking lot at Sequoia Commons, just minutes after having been swept by the Bobcat in the rear.

Monday, August 2, 2010

Violations by Ellis Stone Construction of Stevens Point

On the Ellis website: "Ellis is committed to Green building practices."  "Our team is well versed in sustainable design and construction...."  "We are a proud member of the U.S. Green Building Council."

But at an out-of-the-way site, where inspection is unlikely, the story is different.

At Wildcat Mountain State Park, a new entrance station is under construction by Ellis Stone Construction of Stevens Point.

The fence failed in about four places, spilling much sediment down steep slopes in two directions. The sediment fence was poorly designed--one fence cannot handle this large and steep disturbed area.

In nearby Viroqua, rain of 1.06 inches was recorded on 7/28; 0.36 inches on 7/24; and 1.84 inches on 7/22.   The fence failure probably occurred during the big storm on 7/22.  If this is true, then the fence has gone at least 11 days without repair (7/22-8/2).  And that's assuming Ellis plans to repair it when work resumes on Monday, 8/2.

Poor erosion control elsewhere on site led to a large gully forming in the drive approaching the new building, dumping gravel down a steep slope towards the Kickapoo River.  Likewise, this has gone unrepaired for many days, through several subsequent rains.

Breach in silt fence--unrepaired long enough for new grass to grow.

It's bad enough that poor design allowed the erosion control measures to fail in the first place, harming a State Park.  But the failure to follow up and fix the problems within 24 hours represents serious negligence.

See all the photos here.

Edgewater Hotel reconstruction--a site with special challenges

A new tower for the Edgewater Hotel will rise on the steep, wooded site to the right.

The contractor chosen for the Edgewater Hotel reconstruction must be prepared for some significan erosion-control challenges.  The site has a number of risk factors for a major sediment spill:
  • Close to the lake
  • Steep slopes
  • Caving bank above the shore
  • Cramped site
In addition, the project is controversial and highly visible.  The contractor will either gain a reputation for being GREEN, or for GUNK in the Lake.

Ordinary erosion control measures won't cut the mustard.  The anemic, ordinary methods of erosion control required by Madison didn't begin to protect Lake Wingra from the June 21 storm that ravaged the Edgewood Av project.  That storm was only 1.75 inches.

The Edgewater project has to be prepared for a major storm, like the one that recently pummelled Milwaukee with six inches of rain in a few hours.  In the 1990s, a storm of 7-11 inches flooded Madison and Baraboo.

The new tower will rise on the wooded area to the left.

One challenge is the caving bank of soil, 20-30 feet high, ready to collapse into the lake.  The previous owner should have taken care of this.  Nevertheless, the contractor chosen for this site WILL OWN THIS PROBLEM.

Caving bank by shore, 20+ ft high.  Only roots prevent collapse.

The Contractor Report will be watching--and hold this project to higher standards.

Problems continue at Rawson site on W. Gillman St

As of August 1, the gravel pad at on West Gillman had been moved to the center of the street (outside the Tri-North site) and was now sufficiently long. However, before trucks can get to the pad, they have to traverse a long stretch of dirty street from Henry St, where there are piles of disturbed soil. So the pad still does not seem to be fully functional.

Intersection of Henry & Gillman is still very dirty, and there is no inlet filter at Henry & Gormam preventing this dirt from washing to the lake.

While the Gillman-State St intersection seemed to be cleaner than before, the Gillman-Henry St intersection remained very dirty. An added problem was that, even though Gillman St was marked "closed," public vehicle traffic was moving through it, tracking dirt out.

A clear violation was the new stormwater inlet at the intersection of Gillman and Henry: The inlet was filled with sediment from recent storms, but had no filter.

Towards the upper end of the Gillman St construction area, there was much disturbed soil, and several piles of soil, with no silt socks or other containment measures.

The only measures preventing a major sediment spill from this site
  • A shallow berm (the present gavel pad)
  • Gravel dams in the gutters at the lower end of the street
  • An excavated area at the end of the gutters , lower end (to serve as a small basin)
While Contractor Report notes that these measures are probably sufficient for the current standard (a two-year storm), we believe these would be easily overwhelmed with a larger storm, such as the 6" storm that recently occurred in Milwaukee. We believe erosion control measures in Madison should prepare for larger storms.

More photos from 8/1.