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Wetland name or number A EPREttioNAL AND FLATS WETLAND . Hydrologic Functions Indicators that the site functions to reduce flooding and stream degradation D 4.0. Does the site have the potential to reduce flooding and erosion? D 4.1. Characteristics of surface water outflows from the wetland: Wetland is a depression or flat depression with no surface water leaving it (no outlet) points =4 Wetland has an intermittently flowing stream or ditch, OR highly constricted permanently flowing outlet points = 2 2 Wetland is a flat depression (QUESTION 7 on key), whose outlet is a permanently flowing ditch points = 1 Wetland has an unconstricted, or slightly constricted, surface outlet that is permanently flowing • points = 0 D 4.2. Depth of storage during wet periods:Estimate the height of ponding above the bottom of the outlet. For wetlands with no outlet, measure from the surface of permanent water or if dry, the deepest part. Marks of ponding are 3 ft or more above the surface or bottom of outlet points = 7 Marks of ponding between 2 ft to < 3 ft from surface or bottom of outlet points = 5 3 ❑ Marks are at least 0.5 ft to < 2 ft from surface or bottom of outlet points = 3 ❑ The wetland is a "headwater"wetland points = 3 Wetland is flat but has small depressions on the surface that trap water points = 1 Marks of ponding less than 0.5 ft(6 in) points = 0 D 4.3. Contribution of the wetland to storage in the watershed: Estimate the ratio of the area of upstream basin contributing surface water to the wetland to the area of the wetland unit itself ❑ The area of the basin is less than 10 times the area of the unit points = 5 3 The area of the basin is 10 to 100 times the area of the unit points = 3 The area of the basin is more than 100 times the area of the unit points = 0 ❑ Entire wetland is in the Flats class points = 5 Total for D 4 Add the points in the boxes above 8 Rating of Site Potential If score is: ❑12-16= H 0 6- 11 = M ❑ 0-5= L Record the rating on the first page D 5.0. Does the landscape have the potential to support hydrologic function of the site? D 5.1. Does the wetland unit receive stormwater discharges? Yes = 1 No = 0 1 D 5.2. Is > 10% of the area within 150 ft of the wetland in land uses that generate excess runoff? 1 Yes = 1 No = 0 D 5.3. Is more than 25% of the contributing basin of the wetland covered with intensive human land uses (residential at>1 residence/ac, urban, commercial, agriculture, etc.)? 1 Yes = 1 No = 0 Total for D 5 Add the points in the boxes above 3 Rating of Landscape Potential If score is: l 13= H ❑ 1 or 2=M ❑ 0= L Record the rating on the first page D 6.0.Are the hydrologic functions provided by the site valuable to society? D 6.1. The unit is in a landscape that has flooding problems. Choose the description that best matches conditions around the wetland unit being rated. Do not add points. Choose the highest score if more than one condition is met. The wetland captures surface water that would otherwise flow down-gradient into areas where flooding has damaged human or natural resources (e.g., houses or salmon redds): • Flooding occurs in a sub-basin that is immediately down- gradient of unit. points = 2 0 ❑ • Surface flooding problems are in a sub-basin farther down- gradient. points= 1 ❑ Flooding from groundwater is an issue in the sub-basin. points = 1 ❑ The existing or potential outflow from the wetland is so constrained by human or natural conditions that the water stored by the wetland cannot reach areas that flood. Explain why points = 0 ❑ There are no problems with flooding downstream of the wetland. points = 0 D 6.2. Has the site been identified as important for flood storage or flood 0 conveyance in a regional flood control plan? Yes = 2 No = 0 Total for D 6 Add the points in the boxes above 0 Ratingof Value If score is: ❑ 2-4=H ❑ 1 = M 2 0=L Record the ratingon the first page P 9 Wetland Rating System for Western WA.2014 Update Rating Form-Effective January 1,2015 6 WSDOT Adapted Form-March 2,2015