04/25/2001 Env Bd Packet - Laserfiche WebLink

Home Search

Asleson addressed the surface water flow, stating concerns about the efficiency of installed infiltration tubes in the low area before it leaves the site. Donlin inquired about the preparation of the area, if they were going to grade and drill. Asleson asked John Johnson if he could make some general comments about the subject. John Johnson, Civil Engineer, stated that the infiltration tubes were typically 15'x 2'x 3' and worked like a drain field in situations where there was above normal rain and below 100 year rain. The concern was that the ponds would not work as well over time, because of build up of sediment. The infiltration tubes are installed by building trenches with a backhoe, then covering them up. Donlin admitted that she had reservations with the tamarack plantings, if the cottonwood and the aspen were removed and the tamarack did not do well, it would be barren. She commented on the beauty of the cottonwood and aspen which were planned for removal. Asleson noted that the present state of the area was impacted, with most of the tamarack trees gone after 1967 when the highway was put in. This was an attempt to bring it closer to its original state prior to 1967. Donlin said that by removing the aspen and cottonwood 70% of the significant trees on site would be removed. She feared that if the tamarack plantings were unsuccessful, the area would remain essentially treeless. Asleson stated that the tamaracks were in a wet meadow before the highway went through. Chair Lanyon asked if the Board could make a recommendation not knowing the water impact. Mach stated that a restoration of the tamarack theme could be recommended, because aspen would probably encroach fairly quickly, and tamaracks grow more slowly than cottonwoods and aspen. Asleson noted that the Watershed District would probably not recommend the infiltration tubes. Grundhofer inquired on the lighting of the pylons, if they met the code standards. O'Connell mentioned that there was no reference to color in the ordinance. Asleson indicated the lights were high intensity in the center, but were quickly reduced to reduce glare. Chair Lanyon offered that there had not been a response to the recommendations of the Board at the January 3, 2001 meeting, and added the necessity of hearing from the Rice Creek Watershed District. Donlin agreed and asked if their responses to the recommendations would be at the next meeting, in addition to the proposed choices of vegetation. Asleson indicated that the architect had called to ask for the list of recommended plantings. Donlin urged that the plantings consist of those that would attract bird species, and have several textures and colors including prairie gardens, would soften the big box appearance. Mapco_ &_PezpeartovBoap5 Xtn oq Atvo Aaicecr