Updating the National Updating the National Hydrography Data for Hydrography Data for the Twin Cities with the Twin Cities with

Local Subsurface Local Subsurface Drainage InformationDrainage Information

NHD Stewardship ConferenceNHD Stewardship ConferenceLakewood, Colorado April 15, 2009Lakewood, Colorado April 15, 2009

What is NHD?What is NHD?

NHD is a digital spatial dataset that NHD is a digital spatial dataset that describes the location, extent, and describes the location, extent, and relationships of surface water features relationships of surface water features for the entire nationfor the entire nation

UsesUses– Mapping water resourcesMapping water resources– Sharing/reporting of monitoring data Sharing/reporting of monitoring data

(reach ID)(reach ID)– Incorporated into watershed modelsIncorporated into watershed models

The ProblemThe Problem NHD primarily includes streams and NHD primarily includes streams and

ditchesditches Lacks feature density in urban areasLacks feature density in urban areas

NHD for ex-urban area NHD for urban area (with storm sewers)

Twin Cities Storm Water Pilot Twin Cities Storm Water Pilot Project PhasesProject Phases

Phase I: Acquire and Phase I: Acquire and Assemble Subsurface Assemble Subsurface Drainage Data from Local Drainage Data from Local GovernmentsGovernments

Phase II: Extract Significant Phase II: Extract Significant Features and Integrate into Features and Integrate into NHDNHD

Phase I: Acquiring and Phase I: Acquiring and Assembling Local DataAssembling Local Data

Acquire local data Acquire local data – Mostly CAD formatMostly CAD format

Import into GISImport into GIS Georeference Georeference Integrate into a single databaseIntegrate into a single database

There were many challenges!There were many challenges!

GeoreferencingGeoreferencing

Spatial adjustment tool used to fix georeferencing problem

Georeferenced DataGeoreferenced Data

ConnectivityConnectivity

Interrupted by other feature typesInterrupted by other feature types– maintenance access holesmaintenance access holes

Not Connected Connected

ConnectivityConnectivity

Interrupted by missing surface water featureInterrupted by missing surface water feature– DitchDitch– PondPond

DirectionalityDirectionality

Line features not digitized with Line features not digitized with directionalitydirectionality

Not Directional Directional

AttributesAttributes

Inconsistent attributes between sourcesInconsistent attributes between sources Typically limited attributesTypically limited attributes Attributes may be as graphical annotationAttributes may be as graphical annotation

Phase I: Summary of Phase I: Summary of ChallengesChallenges

Unknown coordinate systemsUnknown coordinate systems Overlapping jurisdictionsOverlapping jurisdictions Lack of directionalityLack of directionality Lack of connectivityLack of connectivity Inconsistent and sparse attributesInconsistent and sparse attributes Lack of metadataLack of metadata

Intermediate Storm Sewer Intermediate Storm Sewer Layer Results Layer Results

It was possible to assemble an It was possible to assemble an intermediate storm sewer layer. intermediate storm sewer layer.

Geo-referenced storm sewer data for 38 Geo-referenced storm sewer data for 38 communities (> 200,000 pipes)communities (> 200,000 pipes)

Only a tiny fraction will be incorporated Only a tiny fraction will be incorporated into the NHD drainage networkinto the NHD drainage network

Could be the beginning of regional storm Could be the beginning of regional storm sewer GISsewer GIS

Several significant issuesSeveral significant issues

Phase II: Incorporate into Phase II: Incorporate into NHDNHD

Select major storm water features to Select major storm water features to add to NHD (Feature Thinning add to NHD (Feature Thinning Analysis)Analysis)

Complete directionalityComplete directionality Create feature subsetCreate feature subset Use NHDGeoEdit Tools to update Use NHDGeoEdit Tools to update

NHDNHD

Feature Thinning AnalysisFeature Thinning Analysis

FactorsFactors– Area drainedArea drained

Pipe Size > 30-inPipe Size > 30-in Path lengthPath length

– Connectivity to Connectivity to currently mapped currently mapped NHD featuresNHD features

Area Covered – New Area Covered – New Features Features

Added 1078 linear drainage features Added 1078 linear drainage features (588 km)(588 km)

Features were pipelines, ditches, Features were pipelines, ditches, connectors, artificial pathsconnectors, artificial paths

Represent 6000 individual pipe Represent 6000 individual pipe featuresfeatures

Connected 363 NHD waterbodies to Connected 363 NHD waterbodies to drainage networkdrainage network

Storm Water Features – St. Storm Water Features – St. PaulPaul

Network Tracing – St. Paul Network Tracing – St. Paul

Hydrologic Unit Hydrologic Unit RedelineationRedelineation

WatershedsWatersheds– Updated major and minor watershed Updated major and minor watershed

boundaries for the Twin Cities (Mississippi) boundaries for the Twin Cities (Mississippi) major watershedmajor watershed

– Lake watershed boundaries for 113 lakesLake watershed boundaries for 113 lakes– Added attribute code to define upstream and Added attribute code to define upstream and

downstream relationshipsdownstream relationships Drainage networkDrainage network

– Enhanced network with hundreds of new Enhanced network with hundreds of new featuresfeatures

Example: Boundary Example: Boundary DisagreementDisagreement

Local hydrologic modifications may cut across the height of land boundary

DEM ReconditioningDEM Reconditioning

““Burn-in” the storm Burn-in” the storm sewer drainagesewer drainage

Adjust elevation of Adjust elevation of the digital the digital elevation model elevation model based on input line based on input line featuresfeatures

30

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90

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0 20

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80 10

0

12

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26

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Lateral Distance (m)

Ele

vatio

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m)

Original Surface

Modified Surface

Revised DelineationRevised Delineation

ConclusionsConclusions It is possible (and useful) to use local It is possible (and useful) to use local

subsurface drainage data for update the NHDsubsurface drainage data for update the NHD NHD is a good surface water model for the NHD is a good surface water model for the

Twin Cities Metropolitan AreaTwin Cities Metropolitan Area NHD update capability was a key featureNHD update capability was a key feature NHD update tools complex to learn; docs NHD update tools complex to learn; docs

need improvementneed improvement There were many difficulties with the base There were many difficulties with the base

data (multiple sources); improving base data data (multiple sources); improving base data would improve NHDwould improve NHD

Questionable data were not added. Questionable data were not added.

Challenges of Base DataChallenges of Base Data

Multiple jurisdictionsMultiple jurisdictions Unknown coordinate systemsUnknown coordinate systems Overlapping jurisdictionsOverlapping jurisdictions Lack of directionalityLack of directionality Lack of connectivityLack of connectivity Inconsistent and sparse attributesInconsistent and sparse attributes Lack of metadataLack of metadata

SolutionSolution

Develop CAD and GIS data standards Develop CAD and GIS data standards for storm sewersfor storm sewers

Collaborative effort Collaborative effort Publish and promote the standardsPublish and promote the standards

– GuidanceGuidance– TemplateTemplate– TrainingTraining– Block grantsBlock grants

Minnesota Storm Water Minnesota Storm Water Standards Working Group Standards Working Group

Develop Exchange Standard for Digital Develop Exchange Standard for Digital Storm water System DataStorm water System Data– MPCA: MS4 Reporting & Emergency ResponseMPCA: MS4 Reporting & Emergency Response

Work through Governor’s Council on Work through Governor’s Council on Geographic InformationGeographic Information– Submit to Standards CommitteeSubmit to Standards Committee– Hydrography Committee Review Hydrography Committee Review

How does storm water guideline interact How does storm water guideline interact with surface water features?with surface water features?– Reference Existing Surface Water Data SetsReference Existing Surface Water Data Sets

CreditsCredits

Project Credits:Project Credits:

- Metropolitan Council:Metropolitan Council:- Steve KloiberSteve Kloiber- Jennifer HinzJennifer Hinz

with assistance from:with assistance from:USGS:USGS:

Paul KimseyPaul KimseyRon WenclRon Wencl

LMIC:LMIC:Sandi KuitunenSandi KuitunenJim KrumrieJim KrumrieSusanne MaederSusanne Maeder

Presentation Credits:Presentation Credits:

Steve Kloiber – MN Steve Kloiber – MN Department of Natural Department of Natural Resources (formerly Resources (formerly Metropolitan Council)Metropolitan Council)

Susanne Maeder – MN Susanne Maeder – MN Land Management Land Management Information Center Information Center (LMIC)(LMIC)

Project Funding: Project Funding:

United States United States Geological SurveyGeological Survey

http://www.metrocouncil.org/planning/environment/NHDUpdateTCMA.pdf

Questions?