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9.B.1. PRSR 07 14 2004 SUPP. MEMOSupplemental Memo Item # 9.6.1. rover MEMORANDUM TO: Parks and Recreation Commission FROM: Michele McPhersoir,-Director of Planning DATE: July 12, 2004 SUBJECT: Results of Misl<e Woodlands Tour Attachments • Narrative -Existing Natural Resources • Excerpt from Project Narrative -River Paxk • Updated Overall Site Plan On Friday, July 9, 2004 Parks and Recreation Commission members Koester and Nziolek, along with staff members Leeseberg and McPherson, walked the approximately 11-acre wooded area in the southwest corner of the proposed Miske project. -The consensus of those visiting the site was that it is a very good quality forest and that there axe very nice overlooks from the forest to the meadow area within the overhead power line corridor. Also on Friday, July 9`", staff received the revised and more-detailed site plan drawings of the proposed River Pazk development. As noted in the project narrative, only 3 acres of the 11- acre forest will remain, once grading is completed. In response, staff believes that the lots noted on the attached site plan should be removed in order ro preserve the maximum amount of forest cover available. This would result in the elimination of approximately 16 single-family lots from the development. Staff looks forward to the discussion of the tour and consideration of the park dedication requirements for this project at the July Parks and Recreation Commission meeting. S:APLdNNINGVCaac FilesV?004\P 0409 Rives PazkV7-L PnrR memo.doc 'EkT3TIlVG l~dATU`RAL RESQLIRCES `-:_. ~v[- ~~~ 1~a-~ Land Cover -Agriculture A majority of the land cover is intensive cultivation. Of the approximately 225 acres on this site, 152 acres are currently in cultivation. Further, there was no evidence of contour farming, filter strips, cover crops or other conservation farming practices being employed on the site. The row crops, over a majority of the land, were running parallel to the slopes, ofren running directly to a water body. According to HydroCAD calculations, 10-yeaz storm events result in drainage of between 37.5 cubic feet per second and 103.7 cubic feet per second. These rates are contingent upon watersheds within the site. Through the development of a storm water system, these rates will be reduced to less than 10 cubic feet per second throughout the site. A reduction in sediment and nutrient loading to the receiving bodies will be commensurate with this reduction in runoff. Land Cover -Woodland Approximately 22.8 acres are currently in woodland. The woodland is located in several areas throughout the western and southwestern portions of the property. The majority is located in two stands. One stand is located on the western property line, and abutting Sunset Ridge. This stand is 11.2 acres in size. Terry Jeffery performed a tree survey on June 1, 2004. Three transect were run through the site and ten randomly selected points were sampled. Each sample point had a radius of 20 feet - 1256.6 square feet or 0.028 acres. It is an uneven aged oak hickory stand. The northern and eastern edge of this stand is experiencing an immdation of invasive species, especially common buckthorn Rhamnus cathartica. The interior of this stand, as well as the southern portion of this stand is of high quality. It is a mature stand with a canopy closure between 85 percent and 100 percent. The species composition includes the following co-dominant species: bitternut hickory Carya cordiformis, black cherry Prunus nigra, burr oak Quercus macrocarpa, pin oak Q. ellisoidalis, white oak Q. alba. Ironwood Ostrya virginiana is found as a subordinate tree species. There is virtually no shrub layer in the southern portion of the stand. The forb layer is comprised of large flowered trillium Trillium grandiflora., false-Solomon's-seal Smilicina racemosa, and spinulose woodfern Dryopteris spinulosa. Aerial cover by the forb layer is between 25 percent and 30 percent by area. The other si~ificant stand of trees occurs in a Type 7 wetland that will be discussed in the next section. While a tree survey was not performed within this stand, a walk through was performed at the time of the delineation and during a subsequent boundary survey. The stand is approximately 8.2 acres in size. The species composition of this stand is tamarack Lark laricina and black spruce Picea nigra, with pockets of paper birch Befula papyrifera adjacent to the excavated ditch. Land Cover -Wetland There is approximately 32.4 acres of wetland located on the site. Wetland types represented by these 32 acres include Type 1 -Seasonally Flooded Basin, Type 2 - Inland Fresh Meadow, Type 3 -Inland Shallow Marsh, Type 4 -Inland Deep Fresh Marsh, Tvpe 6 -Shrub Swamp and Type 7 -Wooded Swamp. Of this total, 1.1 acres is the ditch in the northeasfem portion of the property. Another 0.63 acres is a type 1 wetland located westerly on the property that is currently and has historically been cultivated. West of the current house is a 0.39 acre Type 2 wetland that is partially cultivated annually. A Type 4 wetland exists southerly on the property and intersects the easterly property line with 1.7 acres of this basin occumng on the property. All of these basins show evidence of sediment loading from adjacent agricuhural practices. The Type 4 shows evidence of disturbance resulting from herd animals. The remaining wetland occurs in a large complex in the southwestern portion of the property. This wetland is a complex of Types 2, 3, 4, 6, and 7 intersected by Trott Brook. A large portion of the wetland is a sedge meadow that has been extensively ditched and the sedges and grasses have been hayed. The Type 6 and Type 7 wetland occurs more northerly and abuts the easement for the NSP transmission lines. Together with the previously described woodland to the north, thev form a natural wildlife corridor. The Type 7 was historically dominated by tamarack Larix laricina and black spruce Picea nigra. These aze being replaced by paper birch Benda papyrifera. This transition from an obligate wetland species to an upland species is likely a result of drainage due to the extensive ditching in the area. Topography From just north of the northern boundary of Section 36, the land slopes gently to the north and to the east. There are a few rises and depressions throughout the area. Slopes in this azea range from 1 percent to 5 percent. The areas of depression are largely the Type 1 and Type 2 isolated wetland basins addressed earlier. The upland mixes are designed to be "planted into existing temporary mixes". As such, they do not contain a high percentage of cover crops. Because of this, a cover crop of winter wheat and annual rye amass will be employed. Tree Preservation As discussed previously, a significant portion of the woodland located westerly on the property is of high quality. It is the intent of the developer to preserve that portion which is of highest quality. As shown on the plans for the site, the area of tree preservation will be approximately 3.52 acres. Throughout the stand, though not in large contiguous groups, there are other significant trees. These trees are desirable species (i.e. Querezas, Prunus, and Carya) of significant size, with good growth form and no evident pathogenic infections. Wherever lot placement and road alignment allow, these trees will be preserved. Further to the south, all trees within the Type 7 wetland will remain. It is quite likely that the proposed hydrologic improvements to this large wetland complex will result in increased tamarack propagation. Mortality of three large Ouercus ellipsoidalis was observed during the tree survey performed on June 1, 2004. These trees were located in the southwest quarter of the northeast quarter of the stand. One of the trees had leaved out earlier in the year. The observed conditions were symptomatic of a systemic pathogen such as Oak Wilt. During any tree removal in the area, all oaks exhibiting symptoms indicative of Oak Wilt will be disposed of properly to avoid infection of remaining oaks. The removed oaks will either be burned or be disposed of in a manner approved by city officials and the county forester. In addition, a vibratory plow will be used to sever any roots that may have grafted with adjacent remaining oaks. The high quality stand of trees will be immediately adjacent to the wetland labeled southwest and to the proposed prairie restoration to the east_ This will offer a diversity of habitat and a natural, unfragmented corridor for wildlife. This comdor will continue off the property to the south one-half mile, following Trott Brook, and one-half mile to the west through the large Type 7 wetland and associated woodland. Other trees that will remain during construction are along the western boundary between Sunset Ridge and the proposed development. These trees will not only provide a natural buffer between Sunset Ridge and River Park, they will also serve to extend the natural corridor to the north. Prairie Restoration Within the current NSP easement, we will work with NSP in an attempt to create native prairie. Combined with the wetland restoration and woodland preservation, this would create a large natural corridor with minimal fragmentation. This diversity of habitats in a relatively contiguous pattern will provide a unique opportunity for wildlife habitat. PI2OPGdSBBTRC,.~"YSTEM ~~ 'E r ,, .y w: 't ~~u~ ;r ~ha'-~ ~,~rl~ t„ ' ~ ,: ,. ., ._ ... ,. .... _..v ~u3,,,P ., ~raf,w~i z,. : n , . ~.~ -~~ ..~. . ,~.~ Y. „~,..~.e~,,, ~ ,s ,.. ~..4~s ~~ An extensive trail system is proposed for the area. This trail is depicted on the site drawing labeled Preliminary Grading Plan. Depending upon where the trail is located, it will be a combination of bituminous and wood chip. The proposed system is intended to allow access throughout the development, to parkland, and to the previously mentioned natural areas. Further, it is proposed that interpretive and educational kiosks be erected within the natural areas. The information presented will discuss the ecology of the areas and their significance. These will also be used to inform the public about the potential habitat for Blanding's turtles and measures that can be taken to protect the turtles and their habitat. At the kiosks, benches and/or gazebos will be constructed periodically for the users of the resource. The trail will be constructed to the southwest comer of the property so that it could be connected with a future local or regional trail system, thereby allowing the public access to this system and the amenities preserved and restored in the area. 8 G-~ ~>~1171 ~ ~~ 2. Townhomes a. Building separation 1) Side 20 ft. min. 2) Rear 45 ft. min. between townhome detached Set back from private street curb 1) Side 5 ft. min. 2) Front 20 ft. min. c. Private street width X24 ft. H. PROJECT PHASING It is anticipated that a project will be developed in phases over a five to six year period. a first phase will be in the southeast corner of the project. This ill require utility extensions from the southwest corner and street co ruction northeast to County Road 40. Orrin Thompson Homes plans construct models of all four housing types in this first phase. S equent phases would expand out from the first phase as required to eet market demand. III. NATURAL RESOURCE ANALYSIS This section provides an overall description of the natural resources on the site and the proposed preservation and restoration of these resources as part of the development. A more detailed discussion of the Natural Resources is provided under a separate document entitled Natural Resources Narrative. A. Topography The northern portion of the property is relatively flat. It slopes down gently to the north. The southern portion of the property breaks from a high point centrally located down to the east and the west. B. Soils and Ground Water The soils developed in the deep glacial till of the Anoka Sand Plains. Eighteen soil borings were done on the site. In general, the borings encountered 0 to 2.5 feet of topsoil, underlain by fine to medium grained sand, silty sand, silt and sandy clay. According to well logs, the minimum depth to groundwater is 14 feet with an average depth of 29.7 feet. F:\ENG\63300\2641REPORTS\River Park Narrative.426.doc The soil borings indicate that the soils on the majority of the site are well suited to support structures. Some soils correction is anticipated in the southwest corner of the site. C. Vegetation The site exhibits the following composition of land cover types. Cultivation 152 acres Woodland/Forest 22.8 acres Wetlands 34.1 acres Brush/Grassland 14.2 acres Lawn/Landsca in 3.7 acres The woodland area exists within the western portion of the property in one large stand and several smaller ones. In that portion within Section 25 the greatest composition of the forested area is bitternut hickory, black cherry, burr oak, pin oak, and white oak. Ironwood is found as a subordinate tree species. Along the fringe areas common buckthorn has begun to establish itself. In the lower areas along the flood plain of Trott Brook, the vegetation transitions to more hydrophilic type species. As a result of ditches constructed in this area, the tree stand is a mixture of trees common to wetlands such as tamarack, green ash and paper birch. There are also some scattered stands of box elder and cottonwood. The grassland area is a region that has been under agriculture as recently as 2000. Recently the area has become colonized by brome grasses, fox- tail, and other grasses. D. Wetlands The wetlands were delineated in October 2003 and mapped. The related report is being included with the application. There are five wetlands identified on this property, which total 34.05 acres in area. The first is a ditch that extends west from County Road 40 before turning north where it outlets under 193` Avenue. This is an excavated ditch that has been completed in two stages beginning in 1938 and achieving its' current state by 1957. Total area is 1.68 acres. The second is a basin, southeast, is located in the southeast portion of the property and totals 1.62 acres. It is classified as a Type 5 wetland. The third wetland basin identified, as southwest is located in the F:1ENG1633001264\REPORTS1River Park Narratlve.426.doc southwest portion of the property and has a total area of 29.73 acres. It is a complex of wetland types that lies within the floodplain of Trott Brook. A series of ditches has been excavated through the area in an attempt to make the land suitable to agriculture. Haying activity appears to still transpire in the area. The fourth basin is along the western property boundary in Section 25 and is a Type 1 wetland. At the time of the delineation the area was denuded of vegetation, apparently as a result of the crop being flooded out. It is identified as west and totals 0.63 acres. The fifth basin is behind the current house. It is identified as Basin north and is a Type 2 wetland totaling 0.39 acres. All of these basins have experienced a diminishment of functions and values as a result of associated land uses. In addition, none of these basins have a buffer area and several of the areas are currently being drained via ditches. The development will require the mitigation of 52,008 square feet of wetland for the purpose of drainage and road improvements, especially the new County Road 40 alignment. The wetland mitigation is more defined later iri the narrative. IV. WETLAND ALTERATION The preliminary grading plans show approximately 52,008 square feet of wetland alteration. However, 38,681 square feet of this total would be impacts to the ditch. These impacts would be largely unavoidable with the proposed reconstruction of County Road 40. These linear ditches are unavoidable with the site development. The proposed storm sewer is replacing the function of the ditches. Another 5,832 square feet of the northeast basin will be impacted for the proposed realignment of County Road 40. The 7,495 square foot balance of alteration occurs in six areas, each relatively small, in the southern portion of the site. No DNR Public Waters will be altered by this development. The plans also show 64,475 square feet of new wetland creation. These are created adjacent to existing wetlands. Several of the existing wetlands have degraded significantly due to land use activities in the area. It is proposed that these basins be hydrologically and vegetatively restored. The preliminary plan indicates approximately 31.4 acres of wetlands, which have been degraded due to adjacent land use, suitable for restoration. V. TREE PRESERVATION A significant portion of the woodland located westerly on the property is of high F:\ENG163300\264\REPORTS\River Park Narrative.426.doc 9 quality. It is the intent of the developer to preserve that portion which is of highest quality. As shown on the plans for the site, the area of tree preservation will be approximately 3.52 acres. Additional tree preservation is to occur in the Type 7 wetland and on the property boundary between River Park and Sunset Ridge. VI. LANDSCAPING Landscaping for the proposed development shows a mix of native and hardy tree species consisting of Overstory, Coniferous and Ornamental trees to be planted in single-family areas, boulevards, multi-family areas and park areas. The landscape plans show approximately 1,218 trees to be planted. In general, this consists of boulevard trees in the single-family areas. The multi-family areas have both boulevard and rear yard plantings. Deciduous and Coniferous shrubs will also be provided around the townhome units in plant beds with mulch and edging as indicated by the typical detail shown on the landscape plan. There will be additional deciduous and coniferous trees provided along the northern and northeastern edge of the development adjacent the county roads, including the dedicated right-of-way. These trees are proposed for additional screening and buffering for the single-family and townhomes in this area. Additional trees are have been added at the street entrances, park areas and along the proposed trails along with a landscape median which is proposed at the northeast entrance of the development from County Road 40 to the Public Park. This median will have additional overstory trees and sod groundcover for a continuous green corridor to the proposed public park. The Public Park area will have additional trees around the perimeter to add landscape interest to the park and boulevard areas. Generalized sod and seed areas have also been identified on the landscape plans for both single-family and multi-family areas. Sod is proposed for front\side yards and seed (native residential turf mix) is proposed for rear yards. Large open space areas in the proposed outlots will also have a native residential turf mix application. Sod is also proposed for all rights-of-way areas. A native prairie grass seed mixture is proposed for the open space area under the power lines. All rights-of-ways and multi-family areas shall receive irrigation. Irrigation in single-family residential lots is not required however, it is recommended to promote healthy grow of plant materials. Irrigation shall be at the responsibility of the residential homeowners in single-family lots. VII. Public Parks Two Public parks are proposed for the River Park Development. These two parks are an enhanced amenity for the overall development providing increased open green space and recreational opportunities for residents of River Park. F:\ENG\633001264\REPORTS\River Park Narratlve.426.doc 1 The oval park located in the center of the single-family area is the main focal point for the entire development and will serve as an active recreational area. Some features of this park include additional trees and a trail around the perimeter, open turf areas for active recreation, picnic and gathering areas and a fountain in the pond on each end of the park. The park is also connected to the landscape median as stated earlier. This enhanced feature will provide the River Park Development with a central green corridor amenity. The park located on the south end of the development will serve as a natural park and passive recreational area. Some features of this park include additional trees on the northeast and northwest perimeter; native tree stands along the south side, native prairie grass areas for passive recreation, picnic, and small gathering areas. The south side of this park is adjacent a regional park providing additional opportunities for the River Park Residents. VIII. PUBLIC TRAIL An extensive trail system is proposed for the area. This trail is depicted on the site drawing labeled Preliminary Grading Plan. Depending upon where the trail is located, it will be a combination of bituminous and wood chip. The proposed system is intended to allow access throughout the development, to parkland, and to the previously mentioned natural areas. Further, it is proposed that interpretive and educational kiosks be erected within the natural areas. The information presented will discuss the ecology of the areas and their significance. These will also be used to inform the public about the potential habitat for Blanding's turtles and measures that can be taken to protect the turtles and their habitat. At the kiosks, benches and/or gazebos will be constructed periodically for the users of the resource. The trail will be constructed to the southwest corner of the property so that it could be connected with a future local or regional trail system, thereby allowing the public access to this system and the amenities preserved and restored in the area. IX. SITE GRADING The proposed site grading, in general, retains the current topographical features of the site. The most significant grade change is on the south side of the power line easement where the ground elevation would be lowered by up to 25 feet. The proposed grades provide some walkout and lookout lots and provides positive drainage for all areas of the site. The site grading is expected to be done in phases over about afve-year period. The farmstead buildings will be removed or demolished as part of the development. 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