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September 11, 1992 TO: Councilor Randy McDonald FROM: Gene Shutt, Maintenance Manager SUBJECT: AMAZON CHANNEL - FROM 24TH TO 33RD AVENUE The following is a summary of the Maintenance options we discussed on-site at the Amazon Channel between 24th & 33rd Avenues on September 4th. We have identified the following six options for approaching this project: Option 1 : Use volunteer labor to remove sediment and brush from the channel . If this option is used, city staff could assist by providing tools and equip- ment. We also could haul off sediment and brush that volunteers would pile at pre-determined locations or provide drop boxes that could be used for disposal . This is probably the least expensive of all options but would probably be the most time consuming. While I still have some questions about effectiveness, that question wouldn't be answered until a volunteer effort of this magnitude were actually tried. If this is the option we choose to pur- sue a more thorough discussion of how it might work can take place on Sep- tember 14. Option 2: Limit the scope of the work by removing only the sedimentation near 24th and do nothing with the remainder of the section. We feel the sedimentation is the most critical problem within this area. By limiting our work, we would need to return within a year or two and do some vegetation removal . We feel it's more cost effective to do all work within a section of the channel at the time we are there and not have to return for several years. However, if volunteers were used to remove the willows, that portion of the work could be done any time. If we scaled down the project as de- scribed within this option, it would probably take city staff a week to do the work. Option 3: Hire a contractor to do similar work as described in option two. A contractor would have an equipment advantage over the City as they could use a dragline to remove the sedimentation. A dragline reaches farther than our equipment and eliminates the need to do preparatory work on the bank, which we would need to do to get our equipment close enough to the project area. In addition to cost and the (probable) need to prepare a competitive contract, we may have a problem with contractor availability. There are not a lot of contractors equipped to do this type of work, especially on a project as small as this. A contractor could do this work within a week. Option 4: Another option we discussed (probably the least desirable option) was a reconfiguration of the channel bank. This would entail removing quite a bit of dry dirt along the east bank between the bicycle path and the chan- nel . We would construct a retention basin of sorts, allowing for more water retainage at the mouth of the box culvert at 24th. This approach could re- duce the need for major sediment removal along the channel bottom. Before using this option, I would need more information about hydraulics. This type a project could potentially take about six to eight days to complete.