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HomeMy WebLinkAboutWPO201800019 Other 2017-12-19MEMORANDUM 1739 Allied St., Suite A Charlottesville, VA 22903 540.239.1428 www.ecosystemservices.us info@eco systemservices. us December 19, 2017 TO: Stavros Calos Albemarle County Water Resource Program 401 McIntire Road Charlottesville, VA 22902 434-296-5816x3280 Iscalos@albemarle.org SUBJECT: Pollution Reduction Report — River Run 1.1. Methodology The credit for prevented sediment during storm flow is calculated by estimating yearly erosion rates for a project reach and calculating the associated nitrogen and phosphorus loading. This protocol requires either measured erosion rates using bank pins and surveyed cross sections, or estimated erosion rates using an approved methodology. For this project, the Bank Assessment for Nonpoint Consequences of Sediment (BANCS) methodology was used to estimate erosion rates. The steps to accomplish this protocol included: 1. Perform a geomorphic survey of the project reach. 2. Conduct Bank Erosion Hazard Index (BEHI) and Near Bank Stress (NBS) assessments in accordance with standards set forth by the Chesapeake Bay Field Office (USFWS A, 2004) & (USFWS B, 2004). 3. Estimate bankfull height based on field identified bankfull indicators and hydraulic geometry. 4. Conduct bulk density testing. 5. Estimate erosion rates using USFWS erosion rate curves developed for Hickey Run in Washington, D.C. (Berg et al., 2014). 6. Calculate edge of stream (EoS) sediment, phosphorous, and nutrient reductions as a result of restoration. 1.2. Nutrient & Sediment Loading Estimate Sediment loading was calculated by performing a BANCS assessment to estimate erosion rates and then the associated nutrient loading was calculated based on nutrient concentrations determined by Walter et al. (2007), consistent with the Expert Panel Guidance and shown in table 3. Inputs of the BANCS model include: bank erosion hazard index (BEHI) parameters, near bank stress (NBS) parameters, bank length, bank height, bulk density, and bankfull depth. Changes in BEHI parameters were geolocated using a survey grade GPS along the left and right banks of each reach and were combined with reconnaissance level 1 near bank stress (NBS) ratings to calculate erosion rates in feet per year. The area of bank subject to erosion was taken to be the area between the top and toe of the banks which were located during the geomorphic survey conducted in October 2017. Bank height was calculated for sections between each change in NBS or BEHI parameter which follows the assumption that Pollutant Reduction Report — River Run December 19, 2017 variations in bank height will correspond to a break in at least 1 BANCS parameter. Bankfull height was estimated using bankfull indicators and regional hydraulic geometry curves. Upon further hydrologic and hydraulic analyses, bankfull depths are subject to change. Bulk density testing of stream bank sediments was performed using a modified USDA/NRCS methodology, the results of which are shown in table 1. With these inputs, a volumetric erosion rate could be calculated and multiplied by the bulk density to determine the edge of field (EoF) sediment loading rate shown in table 3. EoF nutrient loading rates were calculated by multiplying the EoF sediment loading rate by the nutrient to sediment ratios shown in table 2. Table 1: Bulk densitv results Bank Length (ft) Bulk Density (lbs/cf) 574.88 73.20 379.07 76.30 Table 2: Nutrient to sediment ratios Associated Pollutant lbs/ton of soil TP 1.05 TN 2.28 Table 3: Pre -restoration pollutant loadina rates Loading Region TSS (tons/yr) TP (lbs/yr) TN (lbs/yr) Edge of Field 196.824 206.665 448.759 1.3. Restoration Efficiency The Expert Panel conservatively assumed a 50% restoration efficiency for calculating pollutant reductions. The Panel also decided that if monitoring proves an efficiency greater than 50%, a revised efficiency may be applied to all previous and subsequent credit releases. This efficiency is applied to the EoF pollutant loads to determine the EoF reductions found in table 4. EoS sediment reduction rates are calculated by applying the non -coastal plain sediment delivery ratio of 0.181 to the EoF sediment reduction rate. The Expert Panel assumed nutrient loading reductions between EoF and EoS were negligible. Also shown below is a table comparing interim rates to the calculated edge of stream reductions and a figure illustrating the steps for calculating EoS pollutant reductions. The calculated reductions are subject to change with adjustments to the bankfull depth. Ecosystem Services A 1739 Allied St., Suite A, Charlottesville, VA 22903 A 540.239.1428 A www.ecosystemservices.us Page 2 of 3 Pollutant Reduction Report - River Run December 19, 2017 1. r Wi`l Figure 1: Steps for calculating EoS pollutant reductions Tnhle 4- Pnst-rPstnrntinn nnllutnnt redurtinn rntPs Loading Region TSS (tons/yr) TP (lbs/yr) TN (lbs/yr) Edge of Field 98.412 103.333 224.379 Edge of Stream 17.813 103.333 224.379 Table 5: Comparison of interim to calculated edae of stream reduction rates Der linear foot of restoration Source TSS (Ibs/ft/yr) TP (lbs/ft/yr) TN (Ibs/ft/yr) Protocol 1 54.616 0.158 0.344 Interim Rate 44.88 0.068 0.075 Ecosystem Services, LLC By: Irl Manager — Principal Engineer Kip Mumaw, PE kip@ecosystemservices.us Attachments: 1. Erosion Rate Map 2. BANCS Parameters Ecosystem Services A 1739 Allied St., Suite A, Charlottesville, VA 22903 A 540.239.1428 A www.ecosystemservices.us Page 3 of 3 Eh w Legend S Erosion Rate (ft/yr) S 0.25-0.62 AL 0.63 - 1.21 a a yi 1.22-2.01IL ' 2.02-3.32 � 22 -eke. +' 21 3.33-4.65 F , imp,{ Mr ' • oNo� p } � .moi +++�� ry 1-.� � � �, ri }. uj Ar ra 7e .16 16 AL ev - � � -F ti Op 333A -� , � iiey i� � - � "�' +' _ ''o � .'7 ' � s-• �� ` yp�o 33,1 .y r' _ � -tom � � '�', •,,. _ €lb � - -40 r_ ` . r F Or yr_ - ` - 1F _ E Va f N. 12.5 �. 50 ��} a -�, , , = r w I!lrrLos MaZil A Feet- i4f • . ,. 1739 ALLIED ST SUITE A, CHARLOTTESVILLE, VIRGINIA T AV W } _ (540) 239 1428 ECOSYSTEMSERVICES.US � N � � w „ SCALE: 1 INCH = 25 FEET PROJECT NO: 17-0034 PM: WKM BANCS RESULTS DRAWN BY: DCL RIVER RUN SOURCE: VGIN (2013) DATE: 11/06/2017 SHEET: 1 OF 1 ID Deposition Bulk Density (lbs/cf) Bank Stratification Bank Angle Bank Material Bank Material Adjustement Surface Protection (%) Root Depth (ft) Root Density N NBS Bank Height (ft) Bankfull Depth (ft) Bank Length (ft) BEHI BEHI Score Adjective 0 82.27663491 0 130 0 12 1 35 High 3.13098679 0.9 4.67 42.12 Very High 1 82.27663491 0 75 0 12 1 35 High 2.951 0.9 2.04 36.9 High 2 82.27663491 0 75 0 10 1 35 High 3.529 0.9 2.47 38.4 High 3 82.27663491 0 110 0 10 1 35 High 3.788 0.9 3.49 42.2 Very High 4 82.27663491 0 110 0 10 0.4 25 High 3.920 0.9 1.35 45.2 Very High 5 82.27663491 0 45 0 10 0.4 25 High 2.628 0.9 9.15 38.1 High 6 82.27663491 0 45 0 15 0.4 25 High 2.179 0.9 0.36 35.9 High 7 82.27663491 0 45 0 15 0.4 25 Low 2.635 0.9 6.61 37.2 High 8 82.27663491 0 45 0 15 1.5 10 Low 2.936 0.9 1.00 33.5 High 9 82.27663491 0 60 0 15 1.5 10 Low 2.860 0.9 2.60 34.0 High 10 82.27663491 0 60 0 6 1.5 10 Low 3.775 0.9 18.23 37.8 High 11 82.27663491 0 60 0 6 1.5 10 Moderate 3.602 0.9 4.57 37.6 High 12 82.27663491 0 70 0 6 1.5 10 Moderate 3.154 0.9 3.45 37.7 High 13 82.27663491 0 70 0 6 1.5 10 Very Low 2.740 0.9 4.75 36.6 High 14 82.27663491 0 70 0 6 1 15 Very Low 3.551 0.9 7.85 39.8 Very High 15 82.27663491 0 85 0 6 1 15 Very Low 5.308 0.9 2.34 43.5 Very High 16 82.27663491 0 85 0 6 1 15 Extreme 5.418 0.9 6.23 43.5 Very High 17 82.27663491 0 85 0 6 1 17 Extreme 5.172 0.9 2.82 43.3 Very High 18 82.27663491 8 85 0 6 1 17 Extreme 5.089 0.9 0.18 51.3 Extreme 19 82.27663491 8 80 0 6 1 17 Extreme 4.729 0.9 8.60 50.1 Extreme 20 82.27663491 0 80 0 6 1 17 Extreme 5.003 0.9 4.96 42.3 Very High 21 82.27663491 0 80 0 6 1 17 Moderate 5.149 0.9 0.88 42.3 Very High 22 82.27663491 0 105 0 6 1 17 Moderate 5.314 0.9 9.21 45.1 Very High 23 82.27663491 0 105 0 6 2.75 20 Moderate 5.079 0.9 3.46 40.4 Very High 24 82.27663491 0 105 0 6 2.75 20 Very Low 4.872 0.9 4.41 40.3 Very High 25 82.27663491 0 105 0 10 2.75 20 Very Low 4.389 0.9 17.27 38.6 High 26 82.27663491 0 95 0 10 2.75 20 Very Low 4.953 0.9 3.18 38.7 High 27 82.27663491 0 95 0 20 2.75 20 Very Low 5.129 0.9 0.54 37.2 High 28 82.27663491 0 65 0 20 2.75 20 Very Low 5.127 0.9 0.39 33.3 High 29 82.27663491 0 65 0 20 1 25 Very Low 5.092 0.9 2.18 37.5 High 30 82.27663491 0 65 0 20 1 25 Low 4.948 0.9 7.33 37.4 High 31 82.27663491 7 65 0 20 1 25 Low 4.528 0.9 11.63 44.1 Very High 32 82.27663491 0 65 0 20 1 25 Low 4.363 0.9 1.14 36.9 High 33 82.27663491 0 65 0 8 1 25 Low 4.313 0.9 5.06 39.8 Very High 34 82.27663491 0 65 0 8 3.25 8 Low 4.142 0.9 3.10 35.5 High 35 82.27663491 0 85 0 8 3.25 8 Low 4.210 0.9 19.75 38.1 High 36 82.27663491 7 85 0 8 3.25 8 Low 4.101 0.9 0.09 45.0 Very High 37 82.27663491 7 95 0 8 3.25 8 Low 4.056 0.9 1.55 46.3 Extreme 38 82.27663491 7 95 0 8 3.25 8 Moderate 4.376 0.9 15.43 46.6 Extreme 39 82.27663491 0 95 0 8 3.25 8 Moderate 4.563 0.9 5.46 39.8 Very High 40 82.27663491 0 95 0 8 1 20 Moderate 4.686 0.9 2.19 44.2 Very High 41 82.27663491 0 60 01 81 1 20 Moderate 4.650 0.9 1.94 40.0 Very High 42 82.27663491 0 60 01 181 1 20 Moderate 4.318 0.9 6.79 37.0 High 43 82.27663491 0 60 01 181 1 20 Very Low 3.677 0.9 10.05 36.3 High ID Deposition Bulk Density (lbs/cf) Bank Stratification Bank Angle Bank Material Bank Material Adjustement Surface Protection (%) Root Depth (ft) Root Density N NBS Bank Height (ft) Bankfull Depth (ft) Bank Length (ft) BEHI BEHI Score Adjective 44 82.27663491 0 75 0 18 1 20 Very Low 4.689 0.9 8.76 38.6 High 45 82.27663491 0 75 0 18 1 20 Low 4.548 0.9 10.01 38.5 High 46 82.27663491 0 60 0 18 1 20 Low 3.135 0.9 12.33 35.6 High 47 82.27663491 0 85 0 18 1 20 Low 3.080 0.9 0.39 38.4 High 48 82.27663491 0 85 0 4 1 20 Low 3.124 0.9 1.90 41.1 Very High 49 82.27663491 8 85 0 4 1 20 Low 3.410 0.9 4.40 49.5 Extreme 50 82.27663491 8 85 0 4 1 20 Moderate 3.266 0.9 17.08 49.3 Extreme 51 82.27663491 0 85 0 4 1 20 Moderate 3.991 0.9 8.18 42.2 Very High 52 82.27663491 8 85 0 4 1 20 Moderate 4.080 0.9 0.99 50.3 Extreme 53 82.27663491 8 85 0 4 1 20 Low 3.996 0.9 4.89 50.2 Extreme 54 82.27663491 8 85 0 4 0.55 10 Low 3.913 0.9 2.35 52.4 Extreme 55 82.27663491 8 70 0 4 0.55 10 Low 3.927 0.9 4.11 50.3 Extreme 56 82.27663491 8 70 0 4 0.55 10 Very Low 3.790 0.9 9.94 50.2 Extreme 57 82.27663491 8 90 0 4 0.55 10 Very Low 3.818 0.9 0.92 53.3 Extreme 58 82.27663491 8 90 0 4 0.55 10 High 3.756 0.9 1.40 53.3 Extreme 59 82.27663491 8 90 0 4 1.5 12 High 3.672 0.9 10.04 49.4 Extreme 60 82.27663491 8 90 0 4 1.5 12 Low 4.209 0.9 8.20 50.0 Extreme 61 82.27663491 0 90 0 4 1.5 12 Low 4.315 0.9 24.06 42.1 Very High 62 82.27663491 0 90 0 4 0.75 10 Low 3.896 0.9 2.88 44.6 Very High 63 82.27663491 0 80 0 4 0.75 10 Low 4.334 0.9 17.85 42.9 Very High 64 82.27663491 0 90 0 4 0.75 10 Low 4.522 0.9 3.82 45.0 Very High 65 82.27663491 8 90 0 4 0.75 10 Low 4.835 0.9 6.78 53.2 Extreme 66 82.27663491 0 90 0 4 0.75 10 Low 5.604 0.9 3.34 45.5 Very High 67 82.27663491 0 90 0 4 0.2 3 Low 5.713 0.9 2.94 47.0 Extreme 68 82.27663491 0 80 0 4 0.2 3 Low 6.938 0.9 8.22 45.2 Very High 69 82.27663491 8 80 0 4 0.2 3 Low 9.418 0.9 9.07 53.3 Extreme 70 82.27663491 8 90 0 4 0.2 3 Low 10.753 0.9 4.31 55.4 Extreme 71 82.27663491 0 90 0 4 0.2 3 Low 12.319 0.9 13.24 47.4 Extreme 72 82.27663491 0 100 0 4 0.2 3 Low 9.557 0.9 3.30 47.9 Extreme 73 82.27663491 0 100 0 4 2 13 Low 5.600 0.9 6.81 42.5 Very High 74 82.27663491 0 100 0 4 2 13 Very Low 3.535 0.9 6.43 40.5 Very High 75 82.27663491 0 75 0 4 2 13 Very Low 3.910 0.9 5.82 37.7 High 76 82.27663491 0 75 0 4 2 13 Moderate 4.153 0.9 14.60 37.9 High 77 82.27663491 0 130 0 8 1.25 15 High 2.131 0.9 26.28 40.4 Very High 78 82.27663491 0 90 0 8 1.25 15 High 2.772 0.9 0.04 40.2 Very High 79 82.27663491 0 90 0 8 0.33 10 Very High 2.769 0.9 0.41 45.2 Very High 80 82.27663491 0 90 0 80 0.33 10 Very High 2.800 0.9 0.59 37.3 High 81 82.27663491 0 90 Boulders 0 80 0.33 10 Very High 3.220 0.9 3.25 14.8 Low 82 82.27663491 0 85 Boulders 0 80 0.33 10 Very High 2.973 0.9 1.43 14.8 Low 83 82.27663491 0 85 Boulders 0 80 0.4 25 Very High 2.886 0.9 1.04 14.8 Low 84 82.27663491 0 85 Boulders 0 25 0.4 25 Very High 2.576 0.9 1.40 14.8 Low 85 82.27663491 0 85 01 251 0.4 25 Very High 1.626 0.9 6.16 35.8 High 86 82.27663491 0 85 01 251 0.4 25 Low 2.092 0.9 6.63 38.0 High 87 82.27663491 0 85 01 61 0.4 25 Low 2.533 0.9 0.35 42.7 Very High ID Deposition Bulk Density (lbs/cf) Bank Stratification Bank Angle Bank Material Bank Material Adjustement Surface Protection (%) Root Depth (ft) Root Density N NBS Bank Height (ft) Bankfull Depth (ft) Bank Length (ft) BEHI BEHI Score Adjective 88 82.27663491 0 85 0 6 0.4 25 Moderate 2.687 0.9 5.11 43.2 Very High 89 82.27663491 0 85 0 6 1 17 Moderate 2.635 0.9 12.27 39.7 High 90 82.27663491 10 85 0 6 1 17 Moderate 0.412 0.9 0.58 32.8 High 91 82.27663491 10 130 0 6 1 17 Moderate 0.337 0.9 0.57 35.3 High 92 82.27663491 10 130 0 6 1 17 Extreme 0.314 0.9 0.17 35.0 High 93 82.27663491 10 130 0 10 1 17 Extreme 3.938 0.9 14.07 54.3 Extreme 94 82.27663491 10 100 0 10 1 17 Extreme 5.558 0.9 3.94 53.9 Extreme 95 82.27663491 10 100 0 10 1 17 High 5.983 0.9 6.44 54.1 Extreme 96 82.27663491 0 100 0 10 1 17 High 5.853 0.9 1.68 44.0 Very High 97 82.27663491 0 100 0 15 1 17 High 5.744 0.9 1.84 43.0 Very High 98 82.27663491 0 100 0 15 0.4 10 High 6.537 0.9 5.72 44.7 Very High 99 82.27663491 0 80 0 15 0.4 10 High 6.535 0.9 3.16 42.1 Very High 100 82.27663491 0 80 0 15 0.4 10 Low 6.802 0.9 9.77 42.2 Very High 101 82.27663491 0 80 0 8 0.4 10 Low 6.821 0.9 10.47 44.4 Very High 102 82.27663491 0 80 0 8 0.4 10 Moderate 7.474 0.9 20.30 44.5 Very High 103 82.27663491 0 95 0 8 0.4 10 Moderate 7.219 0.9 0.28 46.8 Extreme 104 82.27663491 0 95 0 8 0.5 30 Moderate 6.763 0.9 2.80 46.3 Extreme 105 82.27663491 0 95 0 8 0.5 30 Low 4.673 0.9 22.87 45.8 Extreme 106 82.27663491 0 95 0 8 0.5 30 Moderate 4.112 0.9 11.35 45.6 Extreme 107 82.27663491 0 95 0 8 0.5 30 Low 4.108 0.9 9.00 45.6 Extreme 108 82.27663491 0 75 0 8 0.5 30 Low 4.137 0.9 2.17 42.7 Very High 109 82.27663491 0 75 0 10 0.5 30 Low 4.531 0.9 13.96 41.6 Very High 110 82.27663491 0 75 0 15 0.5 30 Low 5.290 0.9 8.22 40.8 Very High 111 82.27663491 0 75 0 15 0.5 30 Very High 5.853 0.9 0.87 40.9 Very High 112 82.27663491 0 75 0 15 0.2 5 Very High 6.567 0.9 13.34 42.3 Very High 113 82.27663491 0 75 0 4 0.2 5 Very High 6.975 0.9 10.89 44.5 Very High 114 82.27663491 0 75 0 4 0.2 5 Very High 5.492 0.9 1.65 44.3 Very High 115 82.27663491 0 95 0 4 0.2 5 Very High 5.158 0.9 0.30 47.3 Extreme 116 82.27663491 0 95 0 4 0.75 12 Very High 5.043 0.9 0.63 45.6 Extreme 117 82.27663491 0 95 0 4 0.75 12 Moderate 5.266 0.9 12.88 45.7 Extreme 118 82.27663491 0 95 0 3 0.75 12 Moderate 4.513 0.9 0.59 45.3 Very High 119 82.27663491 0 95 0 3 0.75 12 Low 4.113 0.9 17.77 45.0 Very High 120 82.27663491 0 95 0 22 0.75 12 Low 3.992 0.9 0.84 41.8 Very High 121 82.27663491 0 95 0 22 3.3 17 Low 3.929 0.9 7.23 35.1 High 122 82.27663491 0 75 0 22 3.3 17 Low 4.313 0.9 7.94 32.6 High 123 82.27663491 0 75 0 22 0.3 3 Low 4.257 0.9 2.05 40.6 Very High 124 82.27663491 0 75 0 5 0.3 3 Low 3.987 0.9 11.69 43.7 Very High 125 82.27663491 0 85 0 5 0.3 3 Low 5.246 0.9 5.92 45.5 Extreme 126 82.27663491 0 85 0 5 0.3 3 Very High 5.595 0.9 24.94 45.6 Extreme 127 82.27663491 0 85 0 15 0.3 3 Very High 4.691 0.9 0.42 43.2 Very High 128 82.27663491 8 85 0 15 0.3 3 Very High 4.580 0.9 0.85 51.2 Extreme 129 82.27663491 8 85 01 151 2.8 17 Very High 4.414 0.9 1.09 44.1 Very High 130 82.27663491 8 85 01 151 2.8 17 Low 4.556 0.9 5.54 44.2 Very High 131 82.27663491 8 85 01 151 1.25 10 Low 4.512 0.9 3.86 48.1 Extreme ID Deposition Bulk Density Bank (lbs/cf) Stratification Bank Angle Bank Material Bank Material Surface Adjustement Protection (%) Root Depth Root Density (ft) N NBS Bank Height (ft) Bankfull Bank Length Depth (ft) (ft) BEHI BEHI Score Adjective 132 82.27663491 8 85 0 5 1.25 10 Low 4.621 0.9 5.25 50.4 Extreme 133 82.27663491 0 85 0 5 1.25 10 Low 4.884 0.9 7.21 42.6 Very High 134 82.27663491 0 85 0 5 1.25 10 High 5.457 0.9 30.04 43.0 Very High 135 82.27663491 0 85 0 5 1.25 10 Low 5.517 0.9 2.32 43.1 Very High 136 82.27663491 8 85 0 5 1.25 10 Low 5.483 0.9 2.62 51.0 Extreme 137 82.27663491 8 85 0 8 1.25 10 Low 5.928 0.9 12.44 51.3 Extreme 138 82.27663491 0 85 0 8 1.25 10 Low 6.080 0.9 12.65 43.4 Very High 139 82.27663491 0 85 0 5 1.25 10 Low 6.042 0.9 1.45 43.4 Very High 140 82.27663491 8 85 0 5 1.25 10 Low 6.482 0.9 3.54 51.6 Extreme 141 82.27663491 8 85 0 5 0.4 5 Low 7.943 0.9 3.87 53.6 Extreme 142 82.27663491 0 85 0 5 0.4 5 Low 11.513 0.9 31.30 46.0 Extreme 143 82.27663491 0 85 0 5 0.4 5 Moderate 7.196 0.9 4.85 45.5 Extreme 144 82.27663491 7 85 0 5 0.4 5 Moderate 5.969 0.9 1.15 52.3 Extreme 145 82.27663491 7 85 01 51 2 15 Moderate 5.559 0.9 3.64 47.8 Extreme 146 82.27663491 7 85 01 51 2 15 Very High 4.890 0.9 9.78 47.2 Extreme 147 82.27663491 0 85 01 51 2 15 Very High 3.963 0.9 6.10 39.2 High