Click for next page ( 11

The National Academies of Sciences, Engineering, and Medicine
500 Fifth St. N.W. | Washington, D.C. 20001

Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement

Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 10
10 CHAPTER 4 STATE DOT AND AGENCY SURVEY SURVEY DESIGN ond survey, and 3 general responses. Many states responded to both surveys. Several respondents noted that they were not The project research team developed and formatted a sur- able to provide comprehensive responses to the question- vey form (questionnaire) that was sent to state DOTs and naires because they lacked completion reports, monitoring some other representative agencies that regulate highway data, and time to complete the survey. projects. The project team anticipated that the agency sur- The largest impediment to survey responses was lack of veys would uncover some new technology and monitoring time for DOT employees to fill out the surveys or provide data related to engineering performance, cost effectiveness, information. In one case, the responder made a new box next and environmental results. Copies of this initial survey were to each question, labeled it "Unknown," and then proceeded mailed out in July of 2001. Based on the findings and limita- to check it. Another employee stated on the survey form that tions of the first survey, a second survey was developed and he had a large amount of information about the different mailed out in April 2002. techniques that his agency employed; however, when the employee was asked to send the information, he stated that he could not do this, as he did not have any spare time. This SURVEY RESPONSE AND FINDINGS problem was completely understandable; however, it severely limited the amount of obtainable information and Initial Survey consequently the ability to compare techniques over a vari- ety of conditions. Twenty-six state DOTs responded to the initial survey. The The second largest impediment was the lack of monitor- most common problems or concerns with environmental ing data. Resources to support monitoring are scarce, and techniques were: (1) limited experience designing, installing, monitoring is often not included in project budgets. Without and monitoring a new or modified technique; (2) lack of long- monitoring, it is hard to make conclusions about hydraulic or term, postconstruction data; (3) lack of hydraulic guidelines; geotechnical performance, the survival of vegetation, and so and (4) general concerns about vegetation failure if not well forth. Another difficulty was compiling comprehensive data established before high-flow events. The most common tech- since individuals seemed hesitant to report failures, even niques employed were geotextile fabrics and variations on though failures may yield valuable information. revegetation techniques. Another obstacle experienced in obtaining information was Following the return of the initial survey, agencies and that environmentally sensitive streambank stabilization tech- subcontractors with the most experience were contacted for niques are usually passed over in favor of more traditional additional information. Useful data were received for rock methods. Survey responses and follow-up correspondence vanes, vanes with j-hooks, boulder clusters, vegetated riprap, suggested that the environmentally sensitive techniques are and vortex weirs. not used often due to lack of data. This creates a "chicken and the egg" problem. There is very little information on these techniques because use is infrequent, and use is infrequent Follow-Up Survey because there is very little information on the techniques. On the plus side, however, several states were able to The project team sent out a second survey to collect more provide quality information. comprehensive and informative responses. These revised A lack of knowledge on the part of the designers, con- surveys asked agency personnel to provide better site and struction contractors, and crew was identified as a factor in reach descriptions and more quantitative information about project failure. The impression was that managers and plan- reach hydrology and characteristics. Responses to the second ners get training and read manuals about techniques, but the survey were informative; however, there were still problems people who are actually designing, specifying, and installing with the quantity and quality of the answers. the measures have received no training. One respondent who Responses were received from a total of 29 states; there did not attribute failures to lack of knowledge on the part of were 26 responses to the first survey, 22 responses to the sec- the designers mentioned that "landscape architects came in

OCR for page 10
11 after the project was complete to vegetate it," perhaps indi- nels than rivers. Significantly, although one-third of the cating a lack of integration among project components. respondents reported recurring problems with the tech- These types of human problems evidently reduce success niques, not one state reported completely unsatisfactory per- rates for environmentally sensitive/biotechnical projects. formance of the measures. The survey results show a major emphasis on application of These trends were considered in preparing the technique these measures to creeks as opposed to rivers. In the 21 states guidelines. For example, the importance of incorporating that have used the techniques, well over 250 projects were plant materials during construction, as opposed to planting done on channels referred to as streams or creeks, while only after traditional protection measures are placed, is stressed. 50 projects were reported on channels with names that In addition, because there is such a bias toward projects in include the word river. Although the use of these terms varies streams and creeks, this report focuses on issues associated regionally, streams and creeks usually refer to smaller chan- with smaller channels.