The EPA has also reported that an elevated amount of arsenic was found in a single water sample downstream.  Naturally, the public has been blowing this out of proportion.  Yes, elevated amounts of arsenic can often be associated with fly ash.  However, it’s important to understand what the testing truly indicates.  From the EPA Press release:

One sample of river water out of numerous samples taken indicated an elevated level of arsenic, however arsenic has been found to be naturally occurring in the environment and further investigation is in progress. Arsenic was not detected in samples taken close to the Kingston Water Intake. Unless people regularly drink untreated river water, the arsenic should not cause any adverse health effects. Surface water sample results in the area of the drinking water intakes did not indicate standards exceedances, but sampling will continue.

That said, contamination is still an issue due to heavy metals.  Also from the EPA release:

Current environmental data from surface water sampling indicates that several heavy metals are present in the surface water slightly above drinking water standards in the area of the spill, but not in the area of the Kingston water supply intake. Drinking water standards are designed to be conservative, and results to date are below concentrations EPA knows to be harmful to humans.

It looks like the TVA is being very careful with the press, and probably with good reason.  There is a lot of cleanup that needs to happen as they move forward.

I think it’s important to note a couple of things in this situation:

• We need to take better care of waste storage areas.
• When it comes to contaminants, accidents can always happen (no matter how hard you try to hide the waste)

For a recent article on the TVA spill, check out this one from the Associated Press.  Then again, you could always read the short CNN version, but it seems to think the spill happened on December 26th…

photo by rwhitlock

The worst part of the whole break is that the storage pond was used as a contaminant storage area, containing a mixture of water and fly ash.  This means that the flood waters would be high in heavy metals, and may contain some other forms of contamination.  According to Knoxnews, contaminant testing is underway and the Tenessee Valley Authority is working on a cleanup plan.

The situation is quite unfortunate, and it seems that greater caution should have been used in dealing with a “contaminant storage area”.  After all the work we civil engineers do to try and maintain water quality, one foul error can undo a lot of progress.

TVA Ash Storage Pond Breach [via stormwater.wordpress.com]

Since October 1, consulting engineers in Quebec have been accorded the right to be selected on the sole basis of their competence and qualifications — not price — for government projects related to health, education or transportation.

This is an interesting concept for the consulting industry.  In some ways, the consulting industry sees less competition.  As long as you are a well-known consultant with a valid price, you could easily win a contract without stretching yourself thin at all.  A consulting firm no longer needs to maintain prices that are as low as another, less reputable firm.  The truth is, a lower bid does not always mean the project ends in the most cost effective manner.  In fact, one might argue that the largest savings in a contract would be in part due to the way in which the consultants treat a certain situation.  A good consultant has the opportunity to save the client much more than just the price difference in an initial bid.

On the other side, this policy would make it significantly harder for a new company to break through and make a name for itself.  No longer would the new company be able to simply “buy” a contract in order to make a positive impression on a new client.  The client does have the option to allow this sort of occurrence if they so choose, but it will not be enforced.

All-in-all, this sort of thing puts a bit more pressure on results and diplomacy.  Is this good or bad?  Well it’ll keep the consultant on their toes for sure.  However, one only hopes it does not become exclusive to the point that most competition is eliminated.

[Quebec engineers face post-project evaluation]

Let me know your take in the comments.

Yet some people don’t think it’s enough.  According to the article:

Perrault’s federation estimates that cities would need at least $123 billion to bring essential public infrastructure up to acceptable levels and an additional $115 billion to build infrastructure to meet the needs of a growing population.

Within that $123 billion, the federation estimates that $31 billion would be needed for water and waste water systems, $21.7 billion for roads, sidewalks and bridges, $22.8 billion for public transit, $7.7 billion for waste management and $40.2 billion for community, recreational, cultural and social infrastructure.

And it’s not just here in Canada.  According to the ASCE website, it estimates that $1.6 trillion is needed to bring US infrastructure up to par.

Prizes range from $200 for 5th place to $1000 for first place.  So give it a go, students.

Photo by Howard N2GOT

I just finished reading an interesting post from Pruned entitled “Deep-Sea Living in the Underground Tunnels of New York City”.  The post is inspired by a recent New York Times article describing a leak in one of the tunnels that brings water to New York City.  It’s an interesting read to say the least, particularly the dark tale of future lifetime repair crews that is introduced near the end.

My favourite part is the comparison between the leakage which has been leaking up to 36 million gallons of water a day and the recent drought in Cyprus, which required 14 million gallons of water to be imported per day.  36 million gallons daily is a lot of water.

FOR IMMEDIATE RELEASE
November 20, 2008

Implementing Lessons Learned from ‘Big Dig’ Tragedy
National Civil Engineering Society Proposes Changes Based on Lessons Learned from NTSB Findings

A section of Boston’s Interstate 90 connector tunnel’s suspended concrete ceiling became detached from the tunnel roof and fell onto a vehicle July 10, 2006, killing one person. The National Transportation Safety Board (NTSB) determined the probable cause of the ceiling collapse was the use of an epoxy anchor adhesive that was not capable of sustaining long-term loads.

In an effort to address the NTSB’s findings and help educate the profession on lessons learned, the American Society of Civil Engineers (ASCE) formed the Task Committee to the NTSB Initiative to review the final investigation report and develop recommendations. After nearly a year of review, the task committee’s report, which was released today, acknowledged the role of specifications as “essential for complete understanding of the work to be performed by the builder.” Engineering judgments, decisions and practices affect the safety, health and welfare of the general public. Specifications are the vehicle through which these decisions and practices are incorporated in construction. Specifications also help determine the compliance of the design with codes and ordinances.

“The safety, health and welfare of the general public is dependent upon engineering judgments, decisions and practices incorporated into structures, machines, products, processes and devices,” according to the task committee report. “Specifications are the vehicle through which these decisions and practices are incorporated in construction.”

The task committee’s report identified four challenges to providing accurate specifications:
Technology outpacing knowledge;
The use of “Sole Source” and “or Equal” proprietary specifications;
Prescriptive vs. performance goals in specification writing; and
Lack of an appropriate forum for the development of construction product criteria in the transportation sector.

To overcome these challenges, the task committee recommended that, as part of their continuing education, design professionals should stay informed regarding new materials and construction products through proactive research and interaction with suppliers, trade and technical associations. They also recommended that, whether drafted on a sole-source or “or equal” basis, specifications reflect the unique requirements of the project using all available resources for the establishment of relevant properties and performance. It was also noted that specifications should include a reasonable level of jobsite quality control mechanisms including inspection and testing and evaluation criteria be better coordinated in order to provide consistent guidance to design professionals in the development of effective specifications. And finally, it was recommended that ASCE conduct and publish a “best practices” review of evaluation, qualification and training processes used outside the United States for the regulation and use of proprietary construction products.

Members of the Task Committee on Response to the NTSB Initiative were:
David Nash, committee chair, president, BE&K Government Group, Inc. and chairman, Jordan-BE&K Federal Group, LLC;
Gene Balter, chief operating officer, HDR Construction Control Operation;
Marco Legaluppi, executive vice president, WBCM;
Rayford W. Jenkins, Jr., senior project engineer, Whitman Requardt and Associates, LLP;
Jim Roskie, chief engineer, Construction, Weeks Marine, Inc.;
David Rothenberg, senior project manager, Clark Foundations, LLC; and
John F. Silva, director, Codes & Standards, Hilti North America.

Go to http://content.asce.org/bigdig2007/bigdig07.html for more details about the Task Committee on Response to the NTSB recommendations.

Founded in 1852, the American Society of Civil Engineers represents more than 146,000 civil engineers worldwide and is America’s oldest national engineering society. For more information, visit www.asce.org.

So, if you’re still with me - I decided to go ahead and do a little research on the issue.  Here’s an original 2006 article from USA Today.  And here’s a bit of an editorial from the Boston Globe that blames it on the lack of an independent “owner’s engineer”.  While I’m always curious where the problem occured, you don’t have to blame anyone to know that the anchors were inadequate and should not have been selected for this particular application.  That’s why I like the Highway Accident Report posted by the ASCE, which gives recommendations to the various parties involved.  It also tells me why I received this email:

To the American Society of Civil Engineers:

1. Use the circumstances of the July 10, 2006, accident in Boston, Massachusetts to emphasize to your members through your publications, Web site, and conferences, as appropriate, the need to assess the creep characteristics of adhesive anchors before those anchors are used in sustained tensile-load applications. (H-07-XX)

The interesting part is that the problem is rooted in a system of manmade waterways that connect the great lakes to the Mississipi River.  Now authorities are looking at a series of solutions, none of which seem to be “ideal” in any sense of the word.   It is indeed a difficult situation - artificial heat and BOD methods would cause problems down the stream without significant post-treatment.  The current electric barrier poses safety risks, and like most physical barriers there is no way to block all larvae and eggs.

So, the most ideal solution from an ecological perspective would be to return the system to it’s original flow path.  Of course, this option is complicated and not as financially feasible.

That’s a tough one, Chicago.  Best of luck.

The drawing I will use in this analysis can be found through a simple google search for “stormwater drawing”.  Here’s a thumbnail of the image:

I chose this drawing because it’s a practical example, and also because the plan is large and complicated.  As such, there should be lots of room for discussion.

Step 1: Conversion using default settings

Starting out using only the default settings for the two programs seems like the most logical place to start.  Using Wintopo’s “one-step vectorization”, I retrieved a beautiful dxf file along these lines:

Using all the default options in img2cad, I came up with this drawing:

Now, both drawings look almost identical to the original when you just see a thumbnail from far away.  So, let’s look at one particular example - the property line on the south side of the site.  Here’s the line created by Wintopo:

And by img2cad:

Img2cad’s results had a tendency to provide slightly more consistent lines, compared to Wintopo’s more choppy results.  However, the difference is almost unnoticeable.

Step 2: Adjusting tolerances

Probably the most significant difference between the two programs is the amount of lines created during the vectorization process.  From the img2cad program, my drawing contained only 83400 polylines.  For the Wintopo results, the drawing had over 307800 polylines.  As such, I tried to adjust some of the tolerances within Wintopo to decrease the amount of polylines produced.  As it turns out, I was unable to get a vectorization for this drawing with significantly less than 300,000 polylines in wintopo.

When I adjusted the tolerance in the img2cad options, I noticed that with higher tolerances, the results no longer matched the original shape of the drawing.  To get the most accurate results, it is probably best to leave the value relatively close to the default tolerance.

Step 3: Working with what we have:

So, in both cases the greatest downfall to vectorization is the large amount of small, choppy lines that are created from stray pixels in your original image.  As such, I thought it would be interesting to try a lisp routine that removed all polylines under a certain length.  I downloaded the routine “tlen.lsp” from this page, and modified it to do what I wanted.  Click here to see the revised routine: LENDEL (1.08 KB).  Now, here is the difference before and after the lisp routine:

Wintopo - Before:

After:

Img2cad - Before:

After:

Conclusions:

It seems that it’s not just the program that dictates the final results in vectorization.  Both programs provided similar results - results that still require a lot of cleanup before they can be used in any practical way.  That said, vectorization may prove handy if you want some reference points to use to snap to, or perhaps in the rare case where your drawing doesn’t require a straight, defined line.

As far as the two programs go, it seems like simplicity wins out.  Img2cad is clearly the more simplistic program to use, and it’s default settings seem to provide more usable results.  The more continuous lines are also more useful in conjunction with the lisp program that I used.  That said, there is certainly a list of wintopo features that I did not even consider.  Wintopo offers a large degree of customization, as long as you’re willing to spend the time figuring out how to go about it.