05-09-2005 Council Packet - Laserfiche WebLink

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' < ■' 1220 Tonkawa Shoreline Alteration November 10,2004 Pages In the section titled Urban Area Policies for Natural Resource Management . Policy 2 states: “2. Retention of natural vegetation will limit the impact of urbanization as visible from the lake. Building heights will be limited to less than the typical tree height. Minimum green belts will be provided with prohibitions against clearcutting or excessive thinning of vegetation. Natural vegetation will be preserved on slopes. Retaining walls will be discouraged except when absolutely necessary to prevent erosioi;, in which case they will be screened with natural vegetation.” In regards to the upper wall, the City Engineer has indicated that from an engineering standpoint thr proposed plan is accq>table. However, fiom an aesthetic standpoint, elimination of the upper wall will be less visually intrusive. The Engineer has indicated to me verbally that the upper wall system could be elimiiuited as long as a 3:1 or flatter slope was maintai ned above the lower wall, and natural vegetation with a strong root system was established at that location. My basic issue with the project is loss of the natural grade of the shoreline, replacing it with the upper retaining wall that may not be stiiedy necessary, and repixing the natural vegetatic-n witli contrived plantings and a garden-like view rather than a natural look. A more natural look could could be accomplished by eliminating the upper wall and replacing it with a gently sloped hillside at a 3:1 or flatter slope. The primary area where excavation occurred to lower the ‘hump ’ is between the two sets of mature black oaks shown on the recent survey. It is my belief that the slope previously was uniform between the bases of those two groupings of oaks, whereas after the grading it seems that just south of the northern group is a sign! ficant cut (which the submitted proposal would reinforce with a wall) and then a flat area to tlie base of the southerly oak group. This area currently has an elevation of 936’-937', whereas our 1992 topography and the actual surveyed tree base elevations suggest it should be a gentle slope from elevation 939* at the north end to 936.6' at the south end. The wall and stairway perpendicular to the shoreline extending from the south end of the house, is of lesser concern to me but mi^t be unnecessary if additiraial fill was brou^t in to Uq>erthe grade further south. This wall will only be minimally visible from the lake. Applicants ’ cross section A1 • A2 is the primary area I would change if the intent is to re-establish the original topographic screening. It could rise from the bottom of the steps (937.0) toward the shoreline 14 ’ to a point with elevation 938.0, then drop to the top of the lower wall (933.6) in a distance of approximately 18 ’, for a final slope of 18:4.4 or about 4:1. The slope parallel with the shore should be unifomi in a line between the two definitive oaks, and that line becomes the drainage divide. The only area ofeoneem is at the north end where this grading will irave to blend in with the more precarious slopes remaining on the neighboring property. Conclusion : I believe a grading plan can be devised that substantially restores the original topograpny without resorting to an upper retaining wall, allowing for a more natural looking shoreline, allowing for replanlingof screening and bank stabilization vegetation to reduce the visual impact of the home ’s close proximity to the lake, and that is more in line with the City’s policies.