Chesapeake Bay Watershed Mapping Environmental Resources

Transcription

1 GIS resources for neighborhood s assessment and planning aimed at watershed restoration and preservation Department of Public Work Bureau of Engineering Watershed Ecosystem and Restoration Services Hala Flores, P.E. Watershed Assessment and Planning Program Manager Ron Bowen, P.E. Director January 6, 2010 Agenda Watershed Resource Data - Why do we need it? - How to access it? - Key Information needed for neighborhood assessments. - Analytical tools to support neighborhood restorations. Basic Introduction to Hydrologic and Hydraulic analysis. - Delineating Drainage Areas - Assessing and Landcover and Soil information to estimate the Runoff Curve Number (RCN). - Assessing the Longest Flow Path and Slope to estimate the flow travel time (Time of Concentration) - Assessing the volume of runoff and the peak discharge from your site of investigation - Assessing the pollutant loads from your site of investigation. Chesapeake Bay Watershed Mapping Environmental Resources Patapsco Bodkin Severn Magothy Patuxent South Patuxent Rhode West Herring Bay Anne Arundel County Watersheds 1

2 Mapping Impairments Anne Arundel County s Category 5 303(d) Listed Waters and TMDLS 2008 All Anne Arundel County watershed are impaired for Sediments Draft Sediment TMDL issued for Patapsco Non Tidal Land Cover Mapping Landcover and Impervious Impervious Cover (%) 27% 32% Anne Arundel County Total Acres = 265,200 Impervious Acres = 45,150 17% Impervious 20% 20% 6% 21% 8% 15% 7% 6% 8% Agriculture Commercial Industrial Open Space Residential Low Density Residential Medium Density Rersidential High Density Transportation/Utility Water Woods Wetlands Public Land 36% Public County lands 26.5% State and Federal lands Local, State, and Federal 5.6% (road right of Way) Private Land 64% Commercial and Industrial Residential 4.0% 5.4% Agriculture, Open Space, Etc. 40.4% 18.1% Private Mapping Problem Areas Stream Headcut Bedload Transport Bank Erosion Suspended Sediment Excessive Sediment Transport Perennial Streams to date = Assessed 345 Miles Rated Poor = 112 Miles 2

3 Mapping Monitoring Biological Assessments To monitor is to correct what you thought you knew and the essence of responsible management, Rosgen 2006 Countywide 207 Samples 2% 15% 41% 42% Good Fair Poor Very Poor Biological Index for Biotic Integrity (BIBI) Score Very Poor Poor Fair Good Rating Conditions and Setting Priorities Severely Degraded Channel in North River Subwatershed of South River Watershed, NR2045.E001 Minimally Degraded Channel in North River Subwatershed of South River Watershed, NR2019.Z019 Streams Assessed 345 Miles 16% 25% 46% 13% Physical/Stability Rating Severly Degraded Degraded Partially Degraded Minimally Degraded Rating Conditions and Setting Priorities Percent Weight of Indicators Landscape Ecology Septics 6.2 BMP Treatment Pollutant Load Runoff Best Water Quality Worst Water Quality 3

4 Anne Arundel County Watershed, Ecosystem, and Restoration GIS Resource Mapping GIS Mapping Tools Locating your Area of Interest 4

5 Navigation/Information/Analysis Tools Zoom In Zoom Out Last View Pan Zoom To Full Extent Magnifier Identify Measure Hyper Linked Information Stream and Problem Area Inventory Photos Hyper Linked Information Real Property Data Search 5

6 Introduction to Watershed Hydrology and Hydraulics Hydrology: The scientific study of the properties, distribution, and effects of water on the earth's surface, in the soil and underlying rocks, and in the atmosphere. Hydraulics: The physical science and technology of the static and dynamic behavior of fluids Green Infrastructure Innovations (CH2MHILL, 2009) Introduction to Watershed Hydrology and Hydraulics Natural Hydrology Altered Hydrology Green Infrastructure Innovations (CH2MHILL, 2009) Detention Basins - Hold and Release the runoff after a few hours (Peak flow shaving). - Centralized facilities result in overwhelming of infiltration capacity and failure. - No reduction of volume of runoff. Post Development Flow Rate (cfs) Predevelopment Post Development with Ponds Time (hours) 6

7 Low Impact Development - Maximize use of open space for SWM storage and treatment - Decentralized design results in more groundwater recharge - Reduction of volume of runoff is achieved. Post Development Post Development with LID Porous Pavement Flow Rate (cfs) Predevelopment Time (hours) Rain Gardens and Porous Sidewalks Designing LID Facilities - Drainage Area Delineation - Landcover Delineation - Soil Type Delineation - Curve Number Estimation Porous Pavement - Runoff Volume Estimation - Sizing the facility Rain Gardens and Porous Sidewalks Designing LID Facilities Heritage Complex Bioretentions Points of Investigation 7

8 Designing LID Facilities Heritage Complex Bioretentions Topography and Flow lines Drainage Area = 5 Acres Designing LID Facilities Heritage Complex Bioretentions Drainage Area Delineation Designing LID Facilities Heritage Complex Bioretentions Land Use Mostly Commercial Agriculture Commercial Industrial Open Space Residential Low Density Residential Medium Density Rersidential High Density Transportation/Utility Water Woods Wetlands 8

9 Designing LID Facilities Heritage Complex Bioretentions Soils (Hydrologic Soil Group) A B C D Mostly D Soils Calculating Runoff Volume Runoff Curve Number for Urban Lands RCN = 98 Calculating Runoff Volume Runoff Curve Number for Natural Lands 9

10 AA Co BMP DP Detention Structure (Dry Pond) 5 10 Detention Dry UGVAULT Underground Storage 5 10 Detention Dry UGS Underground Storage 5 10 Detention Dry ED Extended Detention Extended Detention Dry Extended Detention Structure EDSD Microbasin - Extended MB Detention Structure Dry Extended Detention Dry ASCD Attenuation Swale/Check Dam Filtration ATTENSWA Attenuation Swale Filtration STMCEPTOR Stormceptor Filtration WQINLET Water Quality Inlet (OGS) Filtration POSAND Pocket Sand Filter Filtration GBMP Bioretention Facility Filtration ATTTRENCH Attenuation Trench Infiltration DW Dry Well Infiltration DWIT Dry Well - Infiltration Trench Infiltration Dry Well - Infiltration Trench DWITCE with Complete Exfiltration Infiltration Dry Well - Infiltration Trench DWITCE Dry Well - Infiltration Trench DWITCW Dry Well - Infiltration Trench DWITPE Dry Well - Infiltration Trench DWITWQE with Water Quality Exfiltration Infiltration Extended Detention Structure Dry, Infiltration Trench with EDSDITCE Complete Exfiltration Infiltration IB Infiltration Basin Infiltration Infiltration Trench with Complete IITCE Exfiltration Infiltration INPOND Infiltration Basin No Outfall Infiltration IT Infiltration Trench Infiltration Infiltration Trench, Extended ITVSW Infiltration Trench with Complete ITCE Exfiltration Infiltration Infiltration Trench with Complete ITCEMB Exfiltration, Microbasin Infiltration Infiltration Trench with Partial ITPE Exfiltration Infiltration Infiltration Trench with Water ITWQE OGS Oil Grit Seperator Infiltration Oil Grit Seperator Infiltration Trench with Complete OGSITCE Exfiltration Infiltration PNDTR Same as infiltration basin Infiltration PP Porous Pavement Infiltration SB Infiltration Basin Infiltration Water Quality Infiltration Trench WQITPE WQP Water Quality Trench Infiltration LS Level Spreader 0 0 Other OTHER Other 0 0 Other Redevelop Redevelopment 0 0 Other Pretreatment Pretreatment 0 0 Other Credits Credits 0 0 Other PL Plantings 0 0 Other Extended Detention Structure EDSW Wet Wet Structures EXPOND Wet Pond Wet Structures SM Shallow Marsh Wet Structures SW Wet Structure Wet Structures WP Retention Structure (Wet Pond) Wet Structures Calculating Runoff Volume TR-55 Soil Conservation Service Method (SCS) Q = 2 inches 2inx55Acres 5.5 = 0.91 Acre-ft = 40,000 ft Estimating Pollutant Load Water Quality Equation Based on Simple Method First, the runoff coefficient for each land use type must be derived with the equation: R vu = (0.009 * I u ) Where: R vu = Runoff coefficient for land use type u, inches runoff/inches rain. I u = Percent Imperviousness applicable to the scenario modeled. The pollutant loads are then calculated with the following equation: L = S u (P*P j *R vu *C u *A u *2.72/12) Where: L = Pollutant loads for the watershed understudy, lbs/year P = Precipitation, inches/year (42.9 inches for Washington, D.C. Region) P j = Ratio of storms producing runoff (default 0.9) R vu = Runoff coefficient for land use type u, inchesrun/inchesrain C u = Event Mean Concentration for land use type u, milligrams/liter A u = Area of land use type u, acres Estimating Pollutant Load Literature Values for EMCs and BMP Efficiencies Code Landcover TMDL Category % Impervious TN TP PAS NPS Agriculture Pasture SRC Single Row Crop NPS Agriculture AIR BWI Airport NPS Urban CIT City of Annapolis NPS Urban COM Commercial NPS Urban IND Industrial NPS Urban R11 Residential 1 acre NPS Urban Residential 1 acre with Cluster R11C Development NPS Urban Residential 1 acre with High Density R11CD Cluster Development NPS Urban R12 Residential 1/2 acre NPS Urban R14 Residential 1/4 acre NPS Urban R18 Residential 1/8 acre NPS Urban Residential 20 acre - equivalent to RA R20 zoning NPS Urban R21 Residential 2 acre NPS Urban Residential 2 acre with Cluster R21C Development NPS Urban Residential 2 acre with High Density R21CD Cluster Development NPS Urban RWD Residential Woods NPS Urban TRN Transportation NPS Urban FRW Forested Wetlands Other NPS OPS Open Space Other NPS OPW Open Wetlands Other NPS UTL Utility Other NPS WAT Water Other NPS WDS Woods Other NPS Code County Name TN TP BMP Group Dry Extended Detention Dry with Complete Exfiltration Infiltration with Complete Exfiltration Infiltration with Partial Exfiltration Infiltration Detention Infiltration Quality Exfiltration Infiltration with Partial Exfiltration Infiltration 10

11 Sizing a Filtering System MDE Criteria for Filtering Systems Small Drainage Areas < 1 Acres Must Know: - Runoff Volume to Treat - Properties of Underlying soils - Under-drain Connect/Daylight location Sizing a Filtering System MDE Criteria for Filtering Systems Small Drainage Areas < 1 Acres h f d f Checking Treatment Levels at the Heritage Complex Bioretention Facilities: 0.8 inches of Runoff = [0.8 inches x 5.5 Acres] / 12 in/ft = 0.36 Acre-ft 0.36 Acre-ft = 0.36 Acre-ft x ft 2 /Acre = 15,972 ft 3 Area of Filter Required ft2 = 15,972 ft3 x 2.5 ft / [0.5 ft/day x (1 ft ft) x 1.67 days = 23,910 ft2 Area of Filter Provided ft2 = 1250 x 2 = 2500 ft2 Approximately, 10% of the drainage area is treated for the first 0.8 inches of Runoff. 11

12 Populating the CWP Neighborhood Source Assessment Form using the Anne Arundel County WERS mapping Application Keeping the Anne Arundel County WERS mapping application alive with feedback from the stewards Add Activity Remove Activity Report a Problem New Tools Currently Under Development Anticipated Deployment (March 2010) Publish your accomplishments (Registered Users): 1- Zoom to your area of interest and digitize the extent of your project/activity. 2- Enter attribute/description Information about your project. 3- Post before and after restoration pictures. 4- County staff will review/compile user entries and post to the website on a monthly schedule. Track/Publish your accomplishments (Registered Users): Add Activity Remove Activity Report a Problem New Tools Currently Under Development Anticipated Deployment (February/March 2010) 1- Zoom to your area of interest and digitize the extent of your project/activity. 12

13 Track/Publish your accomplishments (Registered Users): Add Activity Remove Activity Report a Problem New Tools Currently Under Development Anticipated Deployment (February/March 2010) 2- Enter attribute/description Information about your project. 3- Post before and after restoration pictures. Restoration Type: Description: Funding: Comments: Status: Contact: Photos/Documents: Rain Garden, Rain Barrel, Planting, Other (Describe) Location, type, extent, other information private, grant, public, etc. Planning, Design, Under Construction, Complete Name, Phone, Name of photo/document and tool for upload Questions/Comments Ron Bowen, P.E. Director Suzanne Etgen Setgen@aacps.org WSA Coordinator Arlington Echo Outdoor Education Center Anne Arundel County Board of Education Hala Flores, P.E. hala.flores@aacounty.org (410) Program Manager Watershed Ecosystem and Restoration Services Bureau of Engineering Department of Public Works 13