MS4 Mapping & GIS Data Connectivity in the Rocky Branch Watershed

Transcription

1 MS4 Mapping & GIS Data Cnnectivity in the Rcky Branch Watershed Jingting Sun USC MEERM-AWNES Prject City f Clumbia Strmwater & GIS Divisin April 24,

2 Special Thanks T: Internship Supervisrs Karen Swank Kustafik, Christpher D. Cliftn, Tracy Mitchell & Victria Kramer Faculty Advisrs Dr. Allan James, Dr. Gwendelyn Geidel

3 Regulatin Backgrund Clean Water Act NPDES Permit Issued thrugh SC DHEC in 2010 Phase I Medium MS4: Pp. between 100,000 and 250,000 City s Respnsibility: SWMP & BMPs 11 Elements: element 4 Fld Cntrl; element 7 Illicit Discharge and Imprper Dispsal 4 Watersheds Phase Watershed Cntained Waterbdies Hydrlgic Unit Cde I Lwer Saluda River Saluda River, Stps Creek, Kinley Creek Watershed II Cngaree River Watershed Rcky Branch, Cngaree River, Reeder Mill Branch III Brad River Watershed Brad River, Smith s Branch, Crane Creek, Nichlas Creek IV Gills Creek Watershed Gills Creek, Penn Branch, Wildcat Creek, Kilburne Creek

4 Urban Runff Hrtnian Flw Infiltratin-excess runff Dminant flw type n urbanized land Rainfall intensity > infiltratin cap. Rapid: flding, ersin, water pllutin (Schueler & Claytr 1997) (James 2013) Impervius Areas & Stream RBC: nn-supprting stream Bank instability Inadequate habitat fr fish & aquatic insects High level bacteria Pr water quality

5 Study Area & Objectives Rcky Branch Watershed Rcky Branch Creek: 2.2 miles 4 mi 2, 49.1% impervius areas 9 sub-basins Objectives MS4 mapping Strmwater database editing Verify the basin divides Pllutant surce tracking & ther recmmendatins (James 2012)

6 Why Mapping MS4? RBW has been facing flding issues ver the years Essential t flding risk management Where strm intakes are lcated Where strm sewers flws t What are their flw capacities Where the MS4 is inefficient Pllutant Surce Tracking (RBWA 2011)

7 Strmwater Features Strmwater is dispensed thrugh the natural & artificial strmwater infrastructure: Catchbasins Junctin bxes Drainage pints Stream pints Outlet structures Open channels Pnds Drain pipes

8 This image cannt currently be displayed. Methdlgy Search fr Plan Drawings Flat File Search City File Search Print & Mark SW Infrastructure t distinguish MS4 with Sanitary Sewer, Water, Steam, Telephne lines

9 This image cannt currently be displayed. Plan Drawings Thmas Cper Library

10 This image cannt currently be displayed. Field Methds GPS Data Cllectin GPS Device: Trimble GeXT 6000 Sftware: ArcGIS, ArcPad, Trimble GPS Analyst (versin 2.40) Cllect the data n the middle f the SW feature Avid Obstructin: trees, buildings, etc. Recrd: pipe size, directin, materials, etc.

11 This image cannt currently be displayed. Methdlgy Mapping & Edit SW Database Gereference Plan Drawings Add the Plan Drawing int ArcMap Fit t Display Add Cntrl Pints Edit SW Database Snapping Add Pints & pipes based n the drawing r field wrk cmments Pipe Attributes

12 GPS Data Quality GPS Accuracy Signals can be affected by many factrs: satellite clck drift, atmspheric cnditins, measurement nise, and multipath Estimated hrizntal accuracy based n the errr f the satellites Measure f Accuracy: PDOP (psitin dilutin f precisin) Ideal Values: < 1m (after differential crrectin) Active/Inactive Active data: functining SW infrastructure Inactive data: nt functining: e.g. abandned pipes r JB

13 QA/QC- GIS Methds Tplgy Manage pint, line and plygn features when they share cincident gemetry Tplgy Rules fr pipes/streams Gemetric Netwrk Check data cnnectivity Whether all pipes cnnect t the MS4 Is there lp r discnnected features

14 Prject Challenges File Search Limitatin Hard t find the drawing fr a specific building/area: time cnsuming Different names fr the same building: e.g. Cliff Apartment= Apartment 73 Rebuilt r Expanded e.g. Children Develpment Center was relcated Drawings are t ld t use SW inf. is mixed in with thers: hard t read Field Wrk Satellite signal is blcked by tall buildings in dwntwn, r the pints are under bridge CB is full f leaves r sils JB is n busy streets MH is hard t pull up Hard t define whether the MH is SW r SS, Water, Steam, etc. T deep t measure the pipe size Database Editing Cntrl Pints Determinatin: thrugh Tax Parcel r SS pints Lack f pipe size, material & elevatin infrmatin Pipe Size? Sanitary MH Steam MH

15 This image cannt currently be displayed. GIS Data Cnnectivity Tpgraphical Lines As a reference t estimate the directin f the SW flw directin Three types in CC s database: 2 feet, 4 feet & 10 feet Limitatins Field Verificatin Cntur Lines Applicatin The mst reliable way t cnnect the MS4

16 This image cannt currently be displayed. Results SW sewer: 10 miles Drainage pipes: 739 Catch basins: 533 Junctin bxes: 179 Drainage pints: 82 Outlet structures: 2 Area: frm 0.72 k m 2 t 0.91 km 2 Revise USC Subbasin Bundaries

17 This image cannt currently be displayed. Gemetric Netwrk Analysis Trace Upstream fr Sediment Gemetric Netwrk Analysis: Trace Upstream Surce: water leakage repair Sediment near Maxcy Gregg Park

18 This image cannt currently be displayed. Gemetric Netwrk Analysis Trace Dwnstream fr Pllutants White Water near Chemistry & Bichemistry Building Other Illicit Discharges

19 Recmmendatins Hydraulic and hydrlgy analysis Pipe-size infrmatin Estimate the ptential flding pints Subsequent fld-cntrl measures t minimize dwnstream effects Elevatin and depth is still lacking in CC s database Applicatin f Strmwater Management Mdel (SWMM) Nnpint surce pllutin cntrl supprted by GIS BMPs: Strmwater Pllutant Preventin Plans (SWPPP) fr cnstructin activities

20 Cnclusins USC Campus subbasin enlarged frm 0.72 km 2 t 0.91 km 2 Surrunding subbasins, such as University Hill and Mill Villages, reduced accrdingly Similar MS4 mapping is being dne fr ther subbasins and applied t revised watershed map In adjusted USC subbasin there are 10 miles f strm sewers, 739 drainage pipelines, 533 catch basins, 179 junctin bxes, 82 drainage pints, and 2 utlet structures Gemetric analysis tl can trace up r dwn MS4 netwrks fr surce r fate f sed & ther pllutants Narrws pssible surces f cntaminatin Reduces time t ID surce as required by NPDES BMPs