Wetland Mitigation Site Monitoring Report

Transcription

1 Wetland Mitigation Site Monitoring Report Agassiz Valley Water Resource Management Project 2014 (year three of five) Prepared for: The Middle-Snake-Tamarac Rivers Watershed District 453 McKinley Street, PO Box 154 Warren, MN I hereby certify that this field investigation and report was prepared by me or under my direct supervision. Mark D. Aanenson CWD Certification No Date: 1/29/2015 Houston Engineering Inc st Avenue North Fargo, ND Ph. (701) HE Project No

2 Introduction This report documents the third year of monitoring of the wetland replacement site for the Agassiz Valley Water Resource Management Project (The Project) site located in Sections 12 and 13 of T154N R47W and Sections 7 and 18 of T154N R46W in Marshall and Polk County, Minnesota. The purpose of this annual report is to provide a record of the vegetative and hydrology parameters of the wetland mitigation area. This report identifies the field conditions of the wetland replacement site that were observed and measured by Houston Engineering staff. Well and staff gauge readings were taken by Middle-Snake-Tamarac River Watershed District staff. Description of the Site This multipurpose project covers approximately four sections of land in McCrea and Comstock Townships in Marshall County and Brislet and Helgeland Townships in Polk County (Attachment A). The structure straddles the line between Marshall and Polk Counties. The impoundment will stores floodwaters that flow into the Red River of the North by the way of the Snake River and Judicial Ditch No The site is about 62.4 channel miles above the Red River of the North. The city of Warren is six miles west and one mile north of the structure site. On Site Mitigation On-site mitigation was proposed in the north half of Section 7 of T154N R46W in Marshall County. The hydrology of the mitigation site was established by diverting runoff from the project inlet channel. A weir was constructed in the ditch and runoff is diverted during high flows into the mitigation site. Excess water exits the site to the west through two corrugated metal pipes (CMP, Attachment A). The drainage surrounding the mitigation site was also modified to bring runoff to the site. The site was proposed to be a 36.1 acre Circular 39 Type 1 and 3 wetland complex with seasonally flooded and shallow marsh plant communities. A seeding plan for the adjacent upland areas is shown in Table 1. The seed mix was a WRP seeding mix provided by the West Polk NRCS office, and was planted with a Truax drill or similar type. Table 1. Seed Mix for the Upland Areas Grasses Forbs Species Seed lbs./acre Species Seed oz./acre Big Bluestem 4 Prairie Blazing Star 2 Indiangrass 2 Maximillian Sunflower 2 Side Oats Grama 2 Wild Bergamot 2 Canada Wildrye 1 Yarrow 1 Switchgrass 0.5 Stiff Goldenrod 2 1

3 The mitigation site was constructed primarily in 2009 and seeded initially in In 2011 the site was evaluated and determined that a seeding catch was not adequate and a reseeding of the uplands was completed in Monitoring of the wetland consists the following: an inventory of the vegetative communities within the mitigation site, photographs of the site, and observations of the hydrologic conditions. At the end of the monitoring period, a wetland delineation will be conducted to measure and document the new wetland acres created. In 2014, two monitoring wells were placed at sites near the north end of the project area (Attachment B). Staff gauges were planned for each of the large ponds, but were not placed due to high water levels caused by heavy precipitation events. As an alternative, the staff gauge at the outlet of the mitigation site was monitored and considered representative of the water levels in the system pond. This outlet structure was closed for the season on November 14, 2014 when the pool was empty. Also in 2014, an additional vegetation monitoring site was added (Site 5, Appendix B). This upland site is intended to give more detailed and thorough monitoring data regarding the encroachment of weeds into the southern portion of the mitigation area, a potential problem as recognized in the 2013 Mitigation Report. Results General Physical Appearance The "as built" condition of the mitigation site appears to correspond with the locations and sizes shown on the project plans. The total size of the new wetland areas was calculated to be 51.0 acres (Attachment B). Approximately 40 acres are Circular 39 Type 3 wetlands and 11 acres are Circular 39 Type 1 wetlands. Upland buffer areas comprise approximately 25 acres of land surrounding the wetland areas. Photography of the site is included in Attachment C at the end of this report. Hydrology As in the previous monitoring report in 2013, the surface water depths were observed during the September site visit (Table 2). Hydrologic measurements were estimated through visual observation. The well monitoring data were collected between July 2 and October 31, 2014 (Table 3). By September 19, some of the wells began to dry, and by October 3 rd, most were dry to the bottom of the well. 2

4 Table 2. Hydrologic Conditions Observed During Vegetation Monitoring 9/29/14 Site Site 1 Site 2 Site 3 Site 4 Site 5 Estimated Average Water Depth In Wetland Area No surface water and not saturation observed None Uplands Average water depths north of the sample location = 0.5 to 1.0 feet Average water depths west of the sample location = Saturated to 0.5 feet None Uplands Table 3. Agassiz Valley Well Monitoring Well Measurements 2014, water elevation in feet at each measurement date. Staff Gauge* Well 1 Well 2 Well 3 Well 4 n/a Elev. at Natural Ground (ft.) Elev. at Natural Ground (ft.) Elev. at Natural Ground (ft.) Elev. at Natural Ground (ft.) Sample Date elev. Water elev. Water Distance below Surface elev. Water Distance below Surface elev. Water Distance below Surface elev. Water Distance below Surface 7/2/ /14/ /1/ /7/ /15/2014 no data /22/ /29/2014 no data /5/ /12/ /19/ /26/ /3/ /10/ /17/ /24/ /31/ * Converted Staff gauge reading = pool elevation at Ag-Valley outlet (1988 Datum). A rain event occurred on 7/24/14 of 3-5 inches over system depending on location. The gate was closed 7/28/14 through 8/21/14 for work to be done downstream at outlet, thus pool reductions during this time were most likely due to evaporation. 3

5 Vegetation Vegetation observed during the site visit is summarized below in Tables 4-7. Currently, much of the Type 3 Wetland areas (Sample Sites 3-4) consisted of shallow open water habitat. For these two sites, the species listed were observed in the terrestrial and emergent wetland areas near the upland-wetland transition. Most of the species listed are considered native wetland species and are typical for wetlands in the region. The Nonnative/Invasive status is based on a species list included in the US Army Corps of Engineers project permit conditions. The wetland indicator status is taken from the Great Plains Regional Plant list ( Additional emergent wetland species will likely become established in future years. Table 4. Monitoring Date 9/29/14 - Sample Site 1 Wetland Area % Cover Scientific Name Common Name Wetland Indicator Status Nonnative and/or Invasive 90 Typha sp. Cattail OBL no 50 Hordeum jubatum Foxtail Barley FACW no 25 Rumex crispus Curly Dock FAC no <5 Alisma subcordatum Water Plantain OBL no <5 Schoenoplectus fluviatilis River Club-Rush OBL no <5 Beckmannia syzigachne Sloughgrass OBL no <5 Echinochloa muricata Wild Millet FACW no <5 Cirsium arvense Canada thistle FACU yes <5 Schoenoplectus tabernaemontani Softstem bulrush OBL no <5 Bidens cernua Beggartick OBL no <5 Setaria pumila Yellow Foxtail FACU no Table 5. Monitoring Date 9/29/14 - Sample Site 2 Upland Buffer % Cover Scientific Name Common Name Nonnative and/or Invasive 30 Elymus canadensis Canada Wildrye no 20 Melilotus alba White Sweetclover yes 20 Melilotus officinalis Yellow Sweetclover yes 10 Cirsium arvense Canada Thistle yes 10 Andropogon gerardii Big Bluestem no 5 Helianthus maximiliani Maximillian Sunflower no 5 Sorghastrum nutans Indiangrass no 5 Populus deltoides Eastern Cottonwood no <5 Panicum virgatum Switchgrass no <5 Solidago canadensis Canada goldenrod no <5 Oligoneuron rigidum Stiff Goldenrod no <5 Solidago gigantea Giant Goldenrod no <5 Phleum pratense Timothy grass no <5 Elymus trachycaulus Slender Wheatgrass no 4

6 Table 6. Monitoring Date 9/29/14 - Sample Site 3 Wetland Area % Cover Scientific Name Common Name Wetland Indicator Status Nonnative and/or Invasive 40 Typha sp. Cattail OBL no 30 Populus deltoides Eastern Cottonwood FAC no <5 Shoenoplectus tabernaemontani Softstem club-rush OBL no Table 7. Monitoring Date 9/29/14 - Sample Site 4 Wetland Area % Cover Scientific Name Common Name Wetland Indicator Status Nonnative and/or Invasive 30 Typha sp. Cattail OBL no 25 Eleocharis erythropoda Spikerush OBL no 20 Eleocharis asicularis Needle Spikerush OBL no 10 Alisma subcordatum Water plantain OBL no 5 Salix discolor Pussy Willow FACW no 5 Populus deltoides Eastern Cottonwood FAC no <5 Shoenoplectus tabernaemontani Softstem club-rush OBL no <5 Mentha arvensis Field mint FACW no <5 Beckmannia syzigachne Sloughgrass OBL no <5 Juncus nodosus Rush OBL no <5 Ambrosia artemesiifolia Common ragweed FACU yes <5 Erigeron sp. Fleabane --- no <5 Cirsium arvense Canada thistle FACU yes Table 8. Monitoring Date 9/29/14 - Sample Site 5 Upland Buffer % Cover Scientific Name Common Name Nonnative and/or Invasive 50 Erigeron sp. Fleabane no 25 Elymus canadensis Canada Wildrye no 10 Cirsium arvense Canada thistle yes <5 Bidens cernua Beggartick no <5 Echinochloa crus-galli Barnyard grass no <5 Sorghastrum nutans Indiangrass no <5 Elymus trachycaulus Slender Wheatgrass no <5 Setaria glauca Yellow Foxtail no <5 Andropogon gerardii Big Bluestem no <5 Solidago canadensis Canada goldenrod no <5 Helianthus maximiliani Maximillian Sunflower no <5 Lactuca serriola Yellow lettuce no 5

7 Success Criteria Evaluation Currently most of the areas are meeting the success criteria as outlined in the USACE project permit conditions. The hydrology criteria were met (according to well monitoring). The vegetation cover criteria were also met for Type 1 wetlands and Type 3 wetlands. For the upland buffers, the vegetation diversity and cover meet the USACE criteria. The abundance of Sweetclover (Melilotus sp.), which is considered nonnative-invasive, may become an area of concern (see section below). Table 9. Success Criteria defined in the USACE Permit and mitigation site results. Type 1 Wetland areas Type 3 Wetland areas Upland Buffers Hydrology Performance Standard (USACE Permit) Observed Hydrology to 24 in. surface water for 15 days Wells 1 & 2 show surface water to mid- September Saturation or inundation of 6 in. water for 60 days Surface water present through September (Sites 3 & 4) N/A N/A Vegetation and Cover Performance Standard (USACE Permit) Site contains 10+ native-noninvasive species, 70% areal cover by yr. 3, >50% species in wetland areas hydrophytic Site contains 10+ native-noninvasive species, 70% areal cover by yr. 3, >50% of species in wetland areas hydrophytic Site contains 10+ nativenoninvasive species, 70% areal cover by yr. 3 Vegetation and Cover Observed native-noninvasive species at Site 1 1 species nonnativeinvasive 82% of species hydrophytic Areal cover is 100%. 3 native-noninvasive species at Site 3, 11 at Site 4 2 species nonnative-invasive at Site 4 100% species hydrophytic at Site 3, 84% at Site 4 Areal cover 100% except Site 3 with approx. 70%, open water areas also present 11 native-noninvasive species at Sites 2 & 5. 3 nonnative-invasive. Areal cover 100%. Spot mowing recommended for 2015 Areas of Concern Currently, Houston does not have any major concerns with the wetland mitigation activities for the Agassiz Valley Water Resource Management Project Mitigation Site. The site has been completed in accordance with the mitigation plan. In 2013 weed control problems on the adjacent land south of the mitigation site were identified as a concern, but in 2014 this area had been cropped, which reduced the potential for adverse impacts on the mitigation site. Some areas within the upland buffers (near Site 2) have patches of Sweetclover (Melilotus sp.). 6

8 These areas are recommended to be mowed prior to flowering in 2015 to prevent the spread of this species. Conclusions Based on Houston's field monitoring activities, it is our conclusion that Circular 39 Type 3 and Type 1 wetland hydrology has been created within the mitigation area. The wetland area is of adequate size to meet the requirements outlined in the USACE Permit. A significant number of additional wetland areas appear to have developed within the site. Wetland vegetation is present and their populations are becoming established. The upland areas consisting of native prairie species are present and becoming established. Some of the created wetland areas could be considered a Deep Marsh plant community due to the areas of open water. Drier conditions in 2015 and 2016 may result in smaller areas of open water. Spot mowing will be conducted in the upland areas in 2015 to address some patches of Sweetclover. 7

9 Attachment A Mitigation Site Maps

10 SMH MDA,RRS AS SHOWN LOCATION MAP WETLAND MITIGATION SITE AGASSIZ VALLEY WATER RESOURCE PROJECT E 1

11 SMH MDA,RRS AS SHOWN SITE MAP WETLAND MITIGATION SITE AGASSIZ VALLEY WATER RESOURCE PROJECT PROJECT NO APPENDIX E FIGURE 2

12 Attachment B Mitigation Site Monitoring Maps

13 ± 210th St NW site 1 Monitoring Well 2 Monitoring Well 1 Monitoring Well 3 site 2 Monitoring Well 4 site 4 site 3 H:\Fargo\JBN\3400\3429\00_3429_014\Mitigation Site Monitoring\GPS Location map.mxd Site Locations Monitoring Wells Type 1 Wetlands - 11 Ac. Type 3 Wetlands - 40 Ac. Uplands - 25 Ac. site Feet

14 Attachment C Mitigation Site Photographs

15 Site 1 Site 2 Site 3

16 Site 4 Site 5