11-25-2002 Council Packet - Laserfiche WebLink

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A few of the proposed plants can be freely reproducing in the wild given the right conditions. Quaking Aspen. Grow-Ix)w Sumac, Dwarf Bush Honeysuckle, and Fleeceflower are all freely reproducing. Some freely reproducing plants can be very invasive and should only be used where their growA and reproduction is limited by the site conditions. Fleeceflower is one plant that can be \ery invasive and should be used only where it can be controlled. 26. The Seed Mixture and Erosion Tontrol Plan identifles areas to receive one of three mixes of native grasses and forbs. The areas are around the primary pond, along the eastern trail, and in the wetland mitigation area/s and wetland fringes. These native grass and forb blends arc identified as Tall Wet Mesic, Mixed 1 leight Mcsic and Amended Tall Wet Mcsic. Depending on specific site conditions, some of the grasses included in these mixes can grow very tall. These grasses can range from approximately 2 feet to up to 8 or 10 feet in height. In addition, the seeding rate is specified at 15 lbs. per acre for native grasses. 3 lbs. per acre for forbs and 20 lbs. per acre for a nurse crop. As the annual supply of sc.mc of the native grass and forb seeds may be limited, it is important not to sc-cd at to high a rate. However, the seeding rate for the native grasses and forbs appears somewhat low. It will be important that all native grass and forb areas arc seeded at the pro|Jc: rate and time, and i .spccted and maintained by a company with proven experience in the establishment and maintenance of native grasses and forbs. These native areas normally require three growing seasons with carefully administered maintenance bums and/or mowing to become fully established. The commitment to establishing vigorous areas of native grasses and forbs should be addressed. 27. Sheets 1,6.3,1.6.4 and L6.6 show plan view^ and sheets L7.1 iind L7.2 show sections of the entry road and roundabout islands, and cul-de-sac rain garden. The design of the entry- road and roundabout islands will include small ponds, a manmade stream, small waterfalls, limestone boulders and rock formations, enuy monument signs, limestone aggregate trails and walks with special pavement, overlooks, ber ’ . s and associated landscaping. The proposed treatment of these spaces is potentially interesting and very- draniatic. llie water feature will require fairly complex systems and engineering to ensure that it will continue to operate as intend-xl during peak stomi events and over the long temi. Depending on the specifics of the water feature, ongoing maintenance requirements could be signilkant. 'Hie design of this system needs to be re\ iew ed by the City engineer. 28. llie island design includes limestone aggregate patlis/surfaces between the back-of-curb and water feature in the two entry- islands/medians. Paths or watkable surfaces along the water feature in the reurow parts of these islands/medians will attract activities and pedestrian circulation that will result in potentially ha/iirdous traffic conflicts. Paths K>cated in the roundabtiut and wide portion of the entry island can be sepiuated from the roadways by distance and landscape barriers to reduce the pc.tential for conflicts, nie City's traffic engineer needs to review l s issue. 29. From an aesthetic pcrspecti\ e. tlie limestone aggregate patlis'surfaccs pn->posed for the areas between the backnif-curb and the water feature would incorporate groups of limestone boulders, small nursses of .shrubs, perennials and grasses surrounded by a bed of limestone aggregate with an appearance similar to rock mulch. Although this xeriscape 1601 t»02-2~.sv 2,s^o l.\ihIstrom.‘Lan4brm Dcsclopnmu "SiuneBay'Page cS