A Systematic Response to Water Quality Concerns in a City of Alpharetta Park

Transcription

1 A Systematic Response to Water Quality Concerns in a City of Alpharetta Park Presented by: Carla Muscarella, PE, CFM Manhard Consulting, Ltd. GAFM 8 th Annual Technical Conference

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3 Drivers/Reason for Project Lake Windward Complaints 195-acre lake with 2,920-acre drainage area On-site issues with sediment deposition, stream erosion and water quality Stream erosion within downstream neighborhood

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6 Goals of this Study Comprehensive Plan to reduce stream erosion and sedimentation Improve water quality in park wet pond Determination whether park contributes to volume reduction in Lake Windward

7 Project Approach

8 Two Primary Project Elements: Field assessment Modeling analysis

9 Two Primary Project Elements: Field assessment Modeling analysis

10 3 Component Field Assessment Visual Observations Water Quality Sampling Benthic Macroinvertebrate ( Benthic ) Assessment

11 3-Part Field Assessment Visual Observations Water Quality Sampling Benthic Macroinvertebrate ( Benthic ) Assessment

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20 One Year Later.

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30 3 Component Field Assessment Visual Observations Water Quality Sampling Benthic Macroinvertebrate ( Benthic ) Assessment

31 Water Quality Sampling Conducted to: Identify specific pollutants and existing sources of pollution Characterize the waters 4 sampling events during study 17 sampling stations identified

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34 Water Quality Sampling Equipment Utilized Oakton Multi-parameter PCSTester 35 Smart3 Colorimeter Portable Lab Kit

35 Methodology Modified version of the District s Wet Weather Monitoring Program After a rain event of 0.3 of rain, minimum At least 72 hrs of dry weather between events

36 Parameters Evaluated Physiochemical: Temperature Dissolved Oxygen ph Conductivity Analytical: Nitrate Phosphorous Potassium Turbidity

37 Parameters Evaluated Turbidity Georgia standard ranges: Up to 10 NTU clear waters, 50 NTU cloudy, NTU very cloudy/muddy Illustration of 5, 50, and 500 NTU samples

38 Assessment of Data Basis of comparison GaEPD standards for optimal values in streams & water bodies Sampling results grouped & evaluated into four physical areas

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40 A R E A 2

41 A R E A 3

42 A R E A 4

43 Water Quality Sampling Results

44 Park Pond Stations A R E A 1

45 Pond Outlet

46 Pond Outlet

47 Pond Outlet

48 A R E A 2 Thornbury Lake Stations

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51 A R E A 3 Unnamed Trib of Thornbury Lake

52 downstream of lake

53 downstream of lake

54 A R E A 4 Unnamed Trib of Lake Windward

55 Pocket wetland Lake Windward

56 pocket wetland Lake Windward

57 Windward

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59 Water Quality Sampling Conclusions

60 Sampling Conclusions Temperature, ph, conductivity, & DO consistently within acceptable ranges for Georgia streams Closer look at 4 remaining parameters to assess Park s role in pollutant loading at Windward

61 Summary of Phosphates at key locations Sampling Events Location 10/12/11 10/19/11 11/16/11 11/28/11 Exiting Park s Pond (SS 4) 0.00 mg/l 0.03 mg/l 0.07 mg/l 0.15 mg/l Entering Thornbury Lake (SS 8) 0.30 mg/l 0.02 mg/l 0.00 mg/l 0.03 mg/l Entering Thornbury Lake (SS 5 and 6) Avg mg/l 0.74 mg/l 0.51 mg/l 1.12 mg/l Exiting Thornbury Lake (SS 9) 0.06 mg/l 0.01 mg/l 0.02 mg/l 0.13 mg/l Entering Lake Windward (SS 17) 0.03 mg/l 0.00 mg/l 0.07 mg/l 0.00 mg/l Phosphate levels entering Lake Windward within range that could support moderate diversity of aquatic life (< 0.1 mg/l)

62 Summary of Nitrates at key locations Sampling Events Location 10/12/11 10/19/11 11/16/11 11/28/11 Exiting Park s Pond (SS 4) 0.00 mg/l 0.21 mg/l 0.00 mg/l 0.00 mg/l Entering Thornbury Lake (SS 8) 0.14 mg/l 0.00 mg/l 0.00 mg/l 0.01 mg/l Entering Thornbury Lake (SS 5 and 6) Avg mg/l 0.09 mg/l 0.01 mg/l 0.01 mg/l Exiting Thornbury Lake (SS 9) 0.23 mg/l 0.00 mg/l 0.00 mg/l 0.00 mg/l Entering Lake Windward (SS 17) 0.16 mg/l 0.16 mg/l 0.00 mg/l 0.01 mg/l Unpolluted waters that contain warm water fish usually have a nitrate concentration of 1 mg/l or less

63 Summary of Potassium at key locations Sampling Events Location 10/12/11 10/19/11 11/16/11 11/28/11 Exiting Park s Pond (SS 4) 1.8 ppm 2.1 ppm 4.6 ppm 3.8 ppm Entering Thornbury Lake (SS 8) 0.8 ppm 1.6 ppm 2.8 ppm 3.6 ppm Entering Thornbury Lake (SS 5 and 6) Avg. 3.1 ppm 5.15 ppm 4.5 ppm 6.1 ppm Exiting Thornbury Lake (SS 9) 1.7 ppm 1.7 ppm 2.1 ppm 2.5 ppm Entering Lake Windward (SS 17) 1.5 ppm 2.5 ppm 1.7 ppm 3.2 ppm Natural levels of potassium within Georgia streams typically range between 2-3 ppm

64 Summary of Turbidity at key locations Sampling Events Location 10/12/11 10/19/11 11/16/11 11/28/11 Exiting Park s Pond (SS 4) 7.10 NTU 7.28 NTU NTU NTU Entering Thornbury Lake (SS 8) NTU NTU NTU NTU Entering Thornbury Lake (SS 5 and 6) Avg NTU NTU NTU NTU Exiting Thornbury Lake (SS 9) 7.97 NTU 3.67 NTU NTU NTU Exiting Webb Bridge Park (SS 16) NTU 9.92 NTU NTU NTU Entering Lake Windward (SS 17) NTU NTU NTU 8.26 NTU Georgia waters that have 50 NTU s considered cloudy

65 Sampling Conclusions Park contributes very limited pollutants downstream to Windward based on the short-term sampling Pollutants *are* being conveyed onto and generated at the park

66 3 Component Field Assessment Visual Observations Water Quality Sampling Benthic Assessment

67 Benthic Macroinvertebrate Assessment. Benthic Macroinvertebrates good indicators of stream health & watershed conditions Provide gage of stream health over a long chronology Followed GaDNR EPD s S.O.P.

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69 Jab technique Sampled riffles, leaf packs, snags, banks Samples placed in sieve bucket then to sample bottles filled w/ ethanol Bottles transferred to lab

70 Types of Organisms Collected Water boatmen Water striders Backswimmers Water beetles Crane flies Blackworms Crayfish Crayfish worms Mussel Shrimp Twin-spotted spiketail

71 Benthic Results

72 Benthic Results

73 Site Index Scores Refers to the stream health rating Based on 100-point scale Considers 5 categories Richness, Composition, Tolerance, Feeding Group, & Habit Location Index Score/Reach Ranking Upstream Reach Score 34 Fair Downstream Reach Score 22 Poor

74 Prioritized Plan & Projects

75 Recommendations & Projects Construction Projects, Activities & Training Repair/Mitigate/Eliminate runoff-related issues Scheduling recommendations for projects that incorporate plants, animals or weathersensitive treatments Estimated Cost to implement each project

76 Recommendations & Projects Tier 1 Highest Priority - low cost, high need, or combination of the two Tier 2 Over Next 10 Years Tier 3 Beneficial but Low Priority - due to high cost and low need

77 Tier 1 Projects Project ID Description Option Cost 1 Erosion Control 1, 2, or 3 ** $1,700 - $2,600 3 Erosion Control 1 $1,200 4 Erosion Control 1 $1,500 5 Infrastructure Repair 1 or 2 ** $1,400 - $1,800 6 Stream Restoration 1 $160,000 9 Parking Lot Paving 3 $55, Stormwater BMP 1 $54, Erosion Control 1 $1, Algae Reduction 1, 2 $500 - $1, Erosion Control 1 $1, Erosion Control 1 $180, Water Quality Sampling 2 $14,000

78 Tier 1 Projects Stream restoration BMP upstream of park pond Treatment within park pond Localized erosion control measures Range of options for stormwater ditches Additional year of sampling Resurfacing parking areas

79 Tier 1 Projects Project ID Description Option Cost 1 Erosion Control 1, 2, or 3 ** $1,700 - $2,600 3 Erosion Control 1 $1,200 4 Erosion Control 1 $1,500 5 Infrastructure Repair 1 or 2 ** $1,400 - $1,800 6 Stream Restoration 1 $160,000 9 Parking Lot Paving 3 $55, Stormwater BMP 1 $54, Erosion Control 1 $1, Algae Reduction 1, 2 $500 - $1, Erosion Control 1 $1, Erosion Control 1 $180, Water Quality Sampling 2 $14,000

80 Project 6 Stream Restoration

81 Project 10 Sediment Basin

82 Project 12 Pond Treatment

83 Tier 2 Projects Project ID Description Option Cost 2 Stream Restoration 1 $130,000 6 Stream Restoration 2 or 3 $78,000 - $360,000 7 Stormwater BMP 1 $7, Stormwater BMP 1 $120, Erosion Control 2 $146, Trail Resurface 3 $200, Water Quality Sampling 1 $40,000 Tier 3 Projects Project ID Description Option Cost 7 Stormwater BMP 2 or 3** $64,000 - $80,000 8 Stream Restoration 1 $450,000 9 Parking Lot Paving 1 or 2** $630,000-$830, Stormwater BMP 2 or 3** $160,000-$190, Erosion Control 3 or 4** $120,000-$260, Trail Resurface 1 or 2** $1,700,000-$2,300,000

84 Project 8 Stream Restoration

85 Project 13 Constructed Wetland

86 Project 15 Ditch Repairs

87 Project 16 Resurface Trail

88 General Recommendations Training for Parks staff regarding which plants should not be manicured/mowed Sediment from ditches/streams/ponds to be relocated outside of original drainage area Thornbury Lake to consider implementing similar options as park wet pond to facilitate elimination of algae and organic matter

89 Questions?

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