The following provides a summary of information required by Fort Collins Land Use Code under (D) (1) items (a) through (k).

Transcription

1 July 30, 2013 James Dullea Parker Land Investments, LLC S. Kenwood Court Highlands Ranch, Colorado RE: Revised Ecological Characterization Study (ECS) Letter Report for the Proposed Waterfield Development Site Near the Northwest Corner of East Vine Drive and Merganser Drive, Fort Collins, Colorado Jim: This revised letter report is submitted to satisfy the requirements of Section of the Land Use Code of the City of Fort Collins regarding the submittal of an ECS report for proposed development projects. The Waterfield project site is an approximate 60-acre parcel located north of East Vine Drive and west of Merganser Drive in the southwest ¼ of Section 5 (Township 7 North, Range 68 West) in Fort Collins, Colorado (see Figure 1). Ecological characteristics of the property were reviewed and a wetland survey was completed on December 10, Subsequent groundwater monitoring in the project area wetlands was completed on June 7, June 14, and June 19, 2013 to evaluate possible wetland mitigation options for the proposed project. The following provides a summary of information required by Fort Collins Land Use Code under (D) (1) items (a) through (k). ECOLOGICAL STUDY CHARACTERIZATION CHECKLIST (a & i) Existing habitats on the property consist of alfalfa hayfield, non-native grassland, non-native/native grassland mix, weedy edge areas, wetland, pond/mudflat, and cultivated cropland (see attached Figure 2). The majority of the property s surface has been planted to alfalfa (Medicago sativa 1 ) and non-native grass, primarily smooth brome (Bromus inermis), for hay production (see attached Figure 2). Less dominant vegetation species recorded in grass hayfield included cheatgrass (Bromus tectorum), field bindweed (Convolvulus arvensis), common dandelion (Taraxacum officinale), and Canada thistle (Cirsium arvense). The non-native grassland and grass hayfield areas are dominated by smooth brome with lesser amounts of native and non-native annual weeds. The cropland portion of the project area had apparently been plowed at the end of the 2012 growing season and supported essentially no vegetation at the time of the December 10, 2012 field survey. There is one segment of the non-native grassland strip along the south side of the Larimer and Weld Canal that supports a few remnant pockets of native grassland intermixed with non-native grassland. This area is designated as Nonnative/native grassland on Figure 2. Smooth brome is still the dominant species in this area, but there are small pockets where native grasses, including blue grama (Bouteloua gracilis) and sand dropseed (Sporobolus cryptandrus), are supported. Weed dominated areas are supported between alfalfa hayfield and the perimeter of the central wetland area on the property. Dominant species in these fringe areas around the wetland are prickly lettuce (Lactuca serriola), Canada thistle (Cirsium arvense), kochia (Bassia scoparia), and lambsquarters (Chenopodium sp.). The single, isolated wetland delineated on the property exists in a depression (see attached Figure 2) that appears to collect excess irrigation water and may also be the result of a high water table. The central portion of this wetland has held standing water during the growing season in the past and supports no vegetation. Additional information on this wetland is provided under the subsequent Section (b). As a result of past agriculture conversion of the property to cropland and alfalfa hayfield, woody species on the property are limited to trees stands in a few areas not converted to agricultural use. Areas supporting trees are the weedy edge area on the east side of the central wetland with small pockets of Russian olive trees (Elaeagnus angustifolia), the non-native grassland strip along the north property boundary with mature and 1 Scientific nomenclature follows USDA, NRCS Plants Database. Available online at:

2 J. Dullea 7/30/2013 Page 2 of 5 young eastern cottonwood (Populus deltoides) trees and Russian olives, and a non-native grassland swale along the southeast property boundary with young eastern cottonwoods (see attached Figure 2). Most cottonwood trees along the northern property boundary are over 6 inches in diameter and may be classified by the City Forester as significant based on the Fort Collins Land Use Code. The City Forester or a private arborist will need to evaluate the health of these trees in order for their significance status to be determined. Aside from potentially significant trees and the central wetland area, the Waterfield property does not support any significant areas of native vegetation or other unique habitat features. The only other feature of ecological value within 500 feet of the property is the Larimer and Weld Canal along the northern property boundary. Alfalfa hayfield, non-native grassland, and cropland are non-native habitats that have been cleared of native vegetation and woody species, and as a result, support no natural habitat features and have minimal ecological and wildlife habitat value. Canada geese grass will occasionally graze the hayfield areas and grassland areas, and trees on the property may be used for perching, nesting, and foraging by raptors and urban-adapted songbirds. No raptor or other bird nests were located in trees on the property during the December 10, 2012 field survey. Wetland and aquatic habitats are valuable habitats in that they typically support a greater diversity of plants and animals than that found in adjacent dryland habitats. In addition, many wildlife species from adjacent upland habitats rely on wetland habitats for obtaining food, cover, and water on a regular or intermittent basis. Wetlands and associated open water habitats also provide foraging, resting, and breeding habitat for waterfowl, shorebirds, and wading birds. Other species potentially present in wetland and aquatic habitats include tiger salamander, Woodhouse s toad, chorus frog, northern leopard frog, bullfrog, wandering garter snake, redwinged blackbird, common yellowthroat, and song sparrow. The overall habitat value of the Waterfield wetland has been reduced somewhat by the conversion of surrounding native habitats to cropland and hayfield habitats. Because of the late fall timing of the Waterfield field survey there were few wildlife species observations made on the property. Deer and raccoon tracks were noted in the muddy ground associated with the central wetland and a flock of a few hundred Canada geese were recorded resting and grazing in alfalfa hayfield habitat. Fox squirrel nests were also observed in some of the larger cottonwood trees along the north property boundary. The extent of spring and summer waterfowl and waterbird use of the central pond and wetland area is unknown. However, based on the relatively monotypic cattail and bulrush stands around the pond mudflat area, lack of diversity of shallow and deeper water habitats in the mudflat/pond area, and lack of any woody species diversity in the wetlands, it is unlikely the mudflat/pond and adjacent vegetated wetlands receive significant waterfowl and shorebird use in the spring and summer. (b) One isolated wetland area exists on the property in a depression (see attached Figure 2) that appears to collect excess irrigation water. The central portion of this wetland has supported standing water in the past during the growing season and was characterized by an unvegetated mud flat at the time of the December 10, 2012 field survey. Test pits could not be dug in the central mudflat area because the ground was frozen solid, a possible indicator of saturated soils. Small patches of thin layers of ice over some portions of the mudflat provided further indication of a possible high water table. However, test holes monitored in June 2013 indicate that groundwater levels are too deep to assist in the support of these wetlands. Vegetated wetlands around the mudflat/pond area are dominated by common cattail (Typha latifolia) and hardstem bulrush (Schoenoplectus acutus), while the outer and more elevated portions of the wetland are dominated by reed canarygrass (Phalaris arundinacea) with lesser amounts of three-square (Schoenoplectus pungens) and Baltic rush (Juncus balticus) also present. There are also a few small pockets of Russian olive (Elaeagnus angustifolia) trees growing along the eastern edge of the wetland depression. The wetland in this depression was delineated on December 10, 2012 using the methods and techniques specified for "routine on-site delineations" in the publication, Corps of Engineers Wetlands Delineation Manual (USACOE 1987), and supplemented by the document, Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Great Plains Region (USACOE 2010). Northern Engineering of Fort Collins surveyed the wetland boundaries after the delineation was completed and determined the wetland area to be 8.46 acres with the mudflat/open water portion comprising 0.97 acre of this total. The wetland report and a request for a jurisdictional determination were submitted to the U.S. Army Corps of Engineers (Littleton District Office). The U.S. Army Corps of Engineers (COE) determined

3 J. Dullea 7/30/2013 Page 3 of 5 the wetland to be non-jurisdictional since it has no connection to Waters of the U.S. (see attached wetland report and COE response letter). Wildlife use of the pond and wetland area is discussed under the previous Section a & i. Follow-up visits to measure groundwater levels in the wetland area in June 2013 indicated that surface water drainage and/or groundwater support to the wetland may be reduced from historical levels since there was no standing water in the central pond/mudflat area and large portions of surrounding cattail stands appeared to be dead. (c) The Waterfield Property provides relatively unobstructed views of the Front Range foothills. (d) As indicated under (a & i) the Waterfield Property supports little native vegetation, and significant trees and other woody vegetation are restricted to small, relatively linear areas that have not been cultivated. (e) There are no natural drainages on or near the Waterfield Property. (f) There is no suitable habitat for any threatened, endangered, or other sensitive species on or adjacent to the Waterfield Property. No other sensitive or ecologically important species are likely to use the property since the majority of its surface has been converted to agricultural uses. (g) Past agricultural and residential conversion of the lands on the Waterfield Property has eliminated the potential for any special habitat features on the property other than the central wetland. (h) The Larimer and Weld Canal along the north property edge represents the only possible wildlife movement corridor on the Waterfield property. (j) Because of the lack of natural habitat features, other than the wetland on the Waterfield Property, there is only one issue regarding the timing of property development and ecological features or wildlife use of the project area. If the development proposal includes removal of any trees on the property or if construction occurs near an occupied raptor nest during the raptor or songbird nesting season (February through July 31), these activities could result in the loss or abandonment of a nest and would be in violation of the federal Migratory Bird Treaty Act. (k) The majority of the project area has been converted to agricultural land use, project development would have no impact on natural habitats or important habitat features, except for possible impacts to existing trees and the wetland on the property. Because tree removal or construction near trees during the nesting season could result in the loss or abandonment of a nest, it is recommended that tree removal or construction near possible raptor or songbird nest trees occur outside of the nesting season (February 1 July 31), or trees be surveyed to ensure lack of nesting prior to removal or construction activities during the nesting season. This mitigation recommendation would preclude the possible incidental take or disturbance of active songbird or raptor nests. The wetland on the property is greater than 1/3 acre in size, but is not likely to receive significant waterfowl and shorebird use because of the reasons provided under the previous Section a & i. The City of Fort Collins Land Use Code prescribes a 100-foot buffer for wetlands 1/3 of an acre or larger. This buffer standard would be applied from the edge of the delineated wetland. Current development plans indicate development would encroach into the wetland buffer zone and wetlands. The area of wetland encroachment supports relatively low quality wetlands (monotypic stands of reed canarygrass), but the Land Use Code would require the proposed development to provide mitigation for the wetland and buffer zone encroachment. No wetland mitigation is required by the COE since the wetland is an isolated, non-jurisdictional wetland (see attached COE response letter). Typically the City requires one-for-one replacement of wetlands for mitigation. The perimeter edge of delineated wetlands equates to 3,123 linear feet. Of this, 1,026 feet would be adjacent to the proposed development. With the current development proposal, lot lines would encroach into wetlands for 212 feet of the 1,026 feet, resulting in the loss of approximately 0.18 acre of wetlands at the southeast corner of the delineated wetland area. A setback buffer for the remaining 814 feet of wetland perimeter would range from

4 J. Dullea 7/30/2013 Page 4 of to feet for an average buffer width of feet, which would be below the 100-foot buffer requirement. Development plans for the park and school sites to the west and north of the remaining 2,097 feet of wetland perimeter are unknown at this time, but it is likely a wetland setback in excess of 100 feet would be maintained for these developments. Four groundwater monitoring test holes were established to evaluate groundwater levels within the wetland area and the potential for wetland mitigation supported by groundwater. Locations of the test holes in wetlands are depicted on Figure 3. Test Holes 17 and 18 were power drilled as part of the developer s geotechnical evaluation of the property. Test Holes CCA-1 and CCA-2 were hand-augered by Cedar Creek personnel to provide additional groundwater level information within the wetland area. Groundwater levels were measured in Test Holes 17 and 18 on June 7 and 19. Groundwater levels were measured in Test Holes CCA-1 and CCA-2 on June 14 and 19. Table 1 presents the results of the groundwater monitoring efforts. Table 1. Waterfield Groundwater Levels in Existing Wetlands Test Hole Groundwater Depth (in inches) June 7, 2013 June 14, 2013 June 19, no data no data 89 CCA-1 no data CCA-2 no data The higher groundwater measured at CCA-1 on June 19 compared to June 14 was likely the result of capillary rise. 2 CCA-2 was established in a depression within a cattail stand. The June 19 visit recorded water to the surface and standing water in depression areas near the test hole, probably the result of recent heavy rain in the area and not rising groundwater The COE ( ) indicates that wetland hydrology sufficient for the creation of wetlands requires 14 or more consecutive days of flooding or ponding, or a water table 12 in. (30 cm) or less below the soil surface, during the growing season at a minimum frequency of 5 years in 10 (50 percent or higher probability). As indicated in Table 1, groundwater measurements are well below 12 inches except for CCA-2 on June 19, which was probably the result of recent rains rather than a rise in groundwater. Based on this information and the apparent decline observed for existing wetlands (dying cattail stands), creation of additional wetlands to mitigate wetlands lost to development would be difficult without supplemental irrigation, which is not a desirable condition for selfsustaining wetlands. It is also uncertain what effect the loss of irrigation runoff and residential development will have on water regimes in the vegetated wetland and mudflat/pond areas. Future mitigation planning for wetland buffer zone would also need to be dependent on water regimes projected for the wetland after project development. The farmer of the property has indicated that the cropland on the property is irrigated anywhere from 30 to 45 days during growing season at a rate of 1.77 acre-feet/day (6/18/13 from C. Rishell), which translates to 53.1 to acre feet of water applied during the growing season. However, the quantity of excess irrigation water that may flow into the existing wetland depression is unknown. Northern Engineering has estimated that runoff from impermeable surfaces from the proposed Waterfield Project, at full build out, would average approximately 6.78 acre-feet from April through October (6/3/13 from A. Cvar). It is currently proposed that this runoff would be treated and then released into the wetland depression area. Whether this water discharge would be sufficient to maintain the existing wetlands is also unknown. However, based on the fact that the current wetland conditions appear to be declining from reduced levels of surface 2 U.S. Army Corps of Engineers Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Great Plains Region (Version 2.0). Wetlands Regulatory Assistance Program, ERDC/EL TR-10-1, March pp. + appendices.

5 J. Dullea 7/30/2013 Page 5 of 5 water, any plans to use the pond/mudflat area and adjacent wetlands for water detention should help to maintain the wetland and possibly reverse the current trend of wetland decline Because of the uncertainties of sufficient groundwater or surface water runoff to support wetland creation to mitigate projected wetland losses on the Waterfield property, two other options could be pursued to mitigate project-related wetland losses. One would be to purchase 0.18 acre of wetlands from a wetland mitigation bank. The other option, if acceptable to the City of Fort Collins, would be to enhance upland habitat conditions within the buffer zone to increase upland habitat value and diversity surrounding the remaining wetland area. Enhancement of the remaining buffer zone would also be required to mitigate reductions in the required 100-foot buffer setback. Additional supplemental plantings of appropriate native herbaceous and woody vegetation species around the wetland perimeter could significantly enhance upland habitat quality surrounding the wetland and increase overall habitat diversity in the wetland/buffer area over current existing conditions. The Land Use Code also specifies a 50-foot buffer for the Larimer and Weld Canal since it could be used as a wildlife movement corridor. A 50-foot buffer would be maintained along the majority of the canal, but there is a 150-foot strip where a very minor encroachment would occur. The encroachment would be no more than 3 feet, so all lot lines would be at least 47 feet from the top of the canal bank. This minor reduction in the canal buffer would not have and adverse effect on wildlife movement along the Larimer and Weld Canal. A final mitigation consideration is that native or other trees determined to be significant on the property should be preserved to the extent possible. Removal of any trees classified as significant would need to be mitigated with replacement trees, as determined by the City Forester based on the Land Use Code. This concludes Cedar Creek Associates, Inc. s evaluation of the Waterfield Property. If you have any questions or require additional information regarding my evaluation, please give me a call. Sincerely, INC. T. Michael Phelan Principal, Senior Wildlife Biologist attachments: Figure 1, Location of the Waterfield Project Area; Figure 2, Habitat Mapping for the Waterfield Project Area, Figure 3, Locations of Waterfield Test Holes, Wetland Survey Report, and COE Response Letter

6

7

8

9 Waterfield Wetland Survey Report & U.S. Army Corps of Engineers Response Letter

10 January 8, 2013 Terry McKee U.S. Army Corps of Engineers, Omaha District Denver Regulatory Office 9307 South Wadsworth Blvd. Littleton, CO RE: Wetland and Other Waters of the U.S. Delineation for the Waterfield Subdivision Property in Fort Collins, Colorado Dear Terry: This letter is submitted to request a jurisdictional determination and approval of the wetland delineation for a wetland area on the Waterfield Property. The Waterfield Property is an approximate 60-acre parcel located north of East Vine Drive and West of North Timberline Drive and Merganser Drive in the southwest ¼ of Section 5 (Township 7 North, Range 68 West) in Fort Collins, Colorado (see attached Figure 1). The Waterfield Property is proposed for subdivision and development of single-family residences. Cedar Creek Associates, Inc. completed a field wetland and other Waters of the U.S. delineation for the project site on December 10, The objective of the delineation work was to fulfill the requirements of Section 404 of the Clean Water Act regarding the delineation of wetlands and other potential Waters of the U. S. prior to proposed development activities. One wetland area was located and delineated in the project area. Latitude and longitude coordinates for the approximate center of the wetland located on the property are and , respectively (NAD 83 Datum). The main project contact is as follows. Survey Methodology Mr. Jim Dullea Parker Land Investments, LLC S. Kenwood Court Highlands Ranch, CO Phone: (303) j.dullea@comcast.net Prior to initiation of field delineation work, aerial photography and NRCS soils mapping of the project site were reviewed for an overview of site characteristics and to determine the characteristics of soils overlying the project area. Potential hydric soils were identified for evaluation during the field delineation work. Wetland delineation and sampling work for the wetlands within the project area were completed using the methods and techniques specified for "routine on-site delineations" in the publication, Corps of Engineers Wetlands Delineation Manual (USACOE 1987), and supplemented by the document, Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Great Plains Region (USACOE 2010). The project area was evaluated and potential wetland, transition zone, and upland vegetation communities were identified. Using the three-parameter approach via test hole characteristics, the wetland/upland boundaries were flagged. Three formal sample point locations (W-1, W-2, and W-3) were established to characterize the wetland area and adjacent uplands. The sample point locations are depicted on the attached Wetlands Exhibit map.

11 T. McKee 1/8/13 Page 2 of 3 At each sample point, percent total cover of dominant plant species was estimated. Species were then classed as OBL (obligate wetland species), FACW (facultative wetland species), FAC (facultative species), FACU (facultative upland species) or UPL (upland species), based on the USDA, NRCS 2012 National Wetland Plant List ( Soil and hydrologic data were also collected to determine the presence or absence of wetlands at each sample point. A formal field data sheet was completed for each sample point. In addition to the formal sample point locations, adjunct test holes were dug, where appropriate, to gain additional vegetation, soil, and hydrologic information used to aid in the characterization of wetlands, uplands, and transition zones. Data sheets were not completed for test holes. The outer wetland/upland boundary was flagged with pink fluorescent tape and sample points were marked with an orange pin flag tied with pink fluorescent tape for subsequent surveying work. The center portion of the wetland is standing water during the growing season. This portion of the wetland was an unvegetated mudflat with small areas of frozen, ponded water at the time of the December 10, 2012 field survey. The outer boundary of the central mudflat was marked with blue flagging to separate this open water area from vegetated wetlands. Northern Engineering of Fort Collins surveyed the wetland and mudflat/open water boundaries after the delineation was completed. The results of the field delineation are summarized in the following section. A location map, habitat map, wetland map exhibit, and copies of the field data sheets are included as attachments to assist the Corps in completing its evaluation of this project site. 1.0 RESULTS NRCS mapping for Larimer County indicates Aquepts, loamy; Aquepts, ponded; Kim Loam; Fort Collins loam; Nunn clay loam, wet; and Satanta loam are the six soil map units in the project area. The wetland delineated on the property is within the Aquepts, loamy and Aquepts, ponded soil-mapping units. No vegetation, soils, or hydrologic characteristics of wetlands were found in the other soil-mapping units in the project area. The majority of the project area is composed of upland alfalfa hayfield that is associated with the Kim Loam; Fort Collins loam; Nunn clay loam, wet; and Satanta loam soil-mapping units. The single, isolated wetland delineated on the property exists in a depression (see attached Figure 2 and Wetland Exhibit) that appears to collect excess irrigation water and may also be the result of a high water table. The central portion of this wetland typically holds standing water during the growing season and supports no vegetation. Test pits could not be dug in the central mudflat area because the ground was frozen solid, a possible indicator of saturated soils. Small patches of thin layers of ice over some portions of the mudflat provided further indication of a possible high water table. Vegetated wetlands around this mudflat/pond area are dominated by common cattail (Typha latifolia, OBL) and hardstem bulrush (Schoenoplectus acutus, OBL). The outer perimeter portion of the wetland is dominated by reed canarygrass (Phalaris arundinacea, FACW). Small stands of Russian olive (Elaeagnus angustifolia, FACU) grow along the eastern wetland perimeter. The survey completed by Northern Engineering determined the size of the total wetland area to be 8.46 acres with the mudflat/open water portion comprising 0.97 acre of this total. Sample point W-1 was established to characterize the perimeter portion of the wetland depression, while sample point W-2 was established in the more mesic wetland zone around the mudflat open water area. Adjacent uplands, dominated by smooth brome (Bromus inermis, UPL) and annual weedy species, are characterized by sample point W-3. No sample points were established in the alfalfa hayfield portions of the property outside of the smooth brome and weed dominated areas adjacent to the wetland perimeter. Table 1 provides a summary of each sample point.

12 T. McKee 1/8/13 Page 3 of 3 Sample Point TABLE 1 Summary of Waterfield Property Wetland and Upland Sample Point Characteristics Primary & Hydric Soil Secondary Dominant Species Indicator(s) Hydrology Indicator(s) COE Wetland W-1 Phalaris arundinacea FACW F6 B10, C3, D2 PEM1a W-2 Typha latifolia - OBL F6 A3, C1, B10, C3, D2 PEM1a W-3 Bromus inermis UPL none none none Jurisdictional Considerations The wetland delineated on the Waterfield project area is surrounded by alfalfa hayfield uplands and has no wetland, drainage, or irrigation ditch connection to Waters of the United States. Terry, the preceding paragraphs summarize the results of the wetland survey completed for the Waterfield Project Area. Please give me a call if you have any questions. Sincerely, INC. T. Michael Phelan Principal attachments: location map, habitat map, wetland exhibit, and data sheets pc: J. Dullea, Parker Land Investments, LLC. C. Risheill

13

14

15

16

17

18

19

20

21

22

23