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Home My WebLink AboutEX_34_Talasaea Supplemental Report and Analysis 1.9.23 8 January 2023 TAL-1952 Ms. Julia Reeve Development Manager Unico Properties, LLC 1215 Fourth Avenue, Suite 600 Seattle, Washington 98161 Via email: juliar@unicoprop.com REFERENCE: Longacres Unico Property, Renton, Washington SUBJECT: Response to Department of Ecology Comments on the Proposed Sounders FC Center Dear Julia: At your request, I have reviewed the comments made by Neil Molstad of the Department of Ecology regarding critical areas issues, particularly with regard to Feature G, that relate to the proposed development of the Sounders FC new headquarters and training facilities on the Longacres Unico property. I have also reviewed the comments from Jeff Gray of Otak, Inc. in his peer review memoranda dated June 9, 2022, November 2, 2022, and December 22, 2022 in relation to Talasaea’s findings and reports pertaining to critical areas related to the proposed Sounders facilities development. With respect to Feature G, we have concluded that this feature should not be considered a regulated wetland. We take this position on the basis of technical and regulatory (i.e., codes, laws, and ordinances) information. Either basis, by itself, supports our conclusion that Feature G is not a regulated wetland. Our rationale for this position is as follows: Ms. Julia Reeve 9 January 2023 Page 2 of 4 Technical Information a. There is no evidence that the area containing Feature G has ever been determined by any wetland scientist or regulatory agency to have contained wetlands prior to the late 1990s. We have presented numerous report documents and aerial photographic support of this statement. b. As part of the Boeing BCAG Headquarters Building and associated road network development, a pair of stormwater ponds was constructed in an area common with the current Feature G area. This is evidenced by aerial photographs, as well as design drawings by the Sverdrup company on their As-Built plans. c. The stormwater ponds were intentionally constructed. Wetland characteristics within Feature G are then the result of these building and road construction activities. d. The types of plants and their relative abundance found within Feature G reflect a predominance of hydrophytic (i.e., wetland) species; however, only weakly hydrophytic and often dominated by aggressive, non-native species (e.g., reed canarygrass and Himalayan blackberry). Similar plant communities often occur in non-wetland environments. e. Soils within Feature G had the following characteristics: a) silty loam near the surface creating a perched water table with non -saturated soils beneath the aquatard, and b) sharp boundaries on redoximorphic features. The latter suggests relict hydric soils, not what would occur in an active, functioning wetland. f. The ground surface inside of Feature G is higher in elevation (approximately one foot) than the adjacent areas outside Feature G. This suggests imported fill material was used following removal of the stormwater ponds. The fill does not appear to be graded after deposition, thereby creating hu mmocks with small depressions in between. The depressions capture and detain incidental precipitation expressed as inundation within Feature G. The source of that material is unknown, although it is possible that some of the source material came from nearby excavations such as what is now Storm Pond B. g. Antecedent precipitation at the time of the NV5 evaluation was within the range of normal conditions (determination was made using the Army Corps of Engineers Antecedent Precipitation Tool or APT). However, a substantial amount of rain fell in the month preceding their work, which we have documented in the APT graph (see Attachment). The presence of wetland hydrology, therefore, is not necessarily established given the amount of rain that fell in the month prior to their work. Ms. Julia Reeve 9 January 2023 Page 3 of 4 h. GeoEngineers collected soil data for their report dated 7 November 2022. Data were collected on 17 May 2022. Climate conditions were determined to be normal using APT. The month preceding their work was wetter than normal. One of their test plots, B-2, is located approximately 180 ft east of Feature G. The soil layers identified by GeoEngineers were silty sands to medium or fine sand. The water table was observed at 7½ ft below the soil surface. The elevation difference between the eastern edge of Feature G and the location of test plot B-2 is approximately the same. i. Data from four additional soil test plots were collected on 6 January 2023. The soils showed redoximorphic features that clearly had sharp boundaries. Sharp boundaries on redoximorphic features indicates that they are relict. Diffuse boundaries indicate an active seasonal movement of groundwater through the soil during the growing season. We conclude from this that Feature G does not have active wetland hydrology. Regulatory Information a. Talasaea Consultants and Otak have both concluded that the Feature G should not be determined to be a regulated feature. Otak has provided code references that support that position in its reports dated June 9, 2022 and December 22, 2022, such as the City’s codes (RMC 4-3-050B.1 and RMC 4-11-230), and the State’s code for Shorelines (RCW 90.58.030(2)(h) and Growth Management (RCW 36.70A.030). b. Otak also provided reference to the Federal Clean Water Act and that Feature G would not be considered a water of the United States (WOTUS). The recent rule change, as described in 40 CFR Part 120 69434 (§ V.D,1.b ), states, “…Artificially irrigated areas which would revert to upland if the irrigation ceased; artificial lakes or ponds created by excavating and/or diking dry land to collect and retain water and which are used exclusively for such purposes as stock wa tering, irrigation, settling basins, or rice growing; artificial reflecting or swimming pools or other small ornamental bodies of water created by excavating and/or diking dry land to retain water for primarily aesthetic reasons; and waterfilled depressions created in dry land incidental to construction activity (emphasis added) and pits excavated from dry land for the purpose of obtaining fill, sand, or gravel, unless and until construction or excavation operation is abandoned and the resulting body of water meets the definition of ‘waters of the United States.’ 51 FR 41217.” Feature G was initially a stormwater detention facility that was constructed in dry land and was later filled with denser soil compared with the area surrounding Feature G. Ms. Julia Reeve 9 January 2023 Page 4 of 4 In summary, I would like to first acknowledge the professional work done by both the City’s consultant, Jeff Gray of Otak, and Ecology’s Wetland Specialist, Neil Molstad, for their careful and thorough reviews of our critical area studies, findings, and reports. The construction history shown in photographs and as-built plans establishes that Feature G is a highly disturbed landform created by construction activities. I conclude by re-stating our position that we share the City’s finding during its SEPA review period that Feature G is not a regulated feature at the local, State, or Federal level. We hope that you will find this information helpful in confirming the regulatory status of Feature G located on property the Sounders FC propose for development of their new headquarters and practice facilities. If you have any questions or require additional information, please contact David R. Teesdale, PWS or me at (425) 861-7550. Thank you. Sincerely, TALASAEA CONSULTANTS, INC. William E. Shiels Principal Attachment Jul 2020 Aug 2020 Sep 2020 Oct 2020 Nov 2020 Dec 2020 Jan 2021 Feb 2021 Mar 2021 Apr 2021 May 2021 Jun 2021 0 2 4 6 8 10 12 Rainfall (Inches)2021-02-06 2021-01-07 2020-12-08 Antecedent Precipitation vs Normal Range based on NOAA's Daily Global Historical Climatology Network Daily Total 30-Day Rolling Total 30-Year Normal Range 30 Days Ending 30th %ile (in)70th %ile (in)Observed (in)Wetness Condition Condition Value Month Weight Product 2021-02-06 4.13504 6.241732 5.586614 Normal 2 3 6 2021-01-07 3.935039 7.2 10.318898 Wet 3 2 6 2020-12-08 4.320473 8.604725 3.814961 Dry 1 1 1 Result Normal Conditions - 13 Coordinates 47.461767, -122.237057 Observation Date 2021-02-06 Elevation (ft)28.51 Drought Index (PDSI)Incipient wetness WebWIMP H2O Balance Wet Season Weather Station Name Coordinates Elevation (ft)Distance (mi)Elevation Weighted Days Normal Days Antecedent KENT 47.4172, -122.2433 28.871 3.093 0.361 1.393 10307 74 KENT 1.7 SSE 47.372, -122.223 263.123 3.264 234.252 2.233 369 7 RENTON MUNI AP 47.4933, -122.2144 28.871 5.429 0.0 2.443 201 9 SEATTLE TACOMA INTL AP 47.4444, -122.3139 370.079 3.798 341.208 3.005 476 0