Rationales for a reference GIS for Hydrosystems. The ECRINS development
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Philippe Crouzet EEA With support from Walter Simonazzi (ETC/LUSI) and EEA IDS staff PowerPoint PPT Presentation


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Rationales for a reference GIS for Hydrosystems. The ECRINS development E uropean C atchments and RI vers N etwork S ystem. Philippe Crouzet EEA With support from Walter Simonazzi (ETC/LUSI) and EEA IDS staff.

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Philippe Crouzet EEA With support from Walter Simonazzi (ETC/LUSI) and EEA IDS staff

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Rationales for a reference GIS for Hydrosystems. The ECRINS developmentEuropean Catchments and RIvers Network System

Philippe Crouzet EEA

With support from Walter Simonazzi (ETC/LUSI) and EEA IDS staff


  • Reference GIS for hydrosystems is prerequisite to producing accurate and representative assessments as well as offering host to legal reporting.

  • To this end, and considering the strong relationships between land, water and economy the system must consist in:

    • Calculable and nested catchments.

    • Drained by relevant, nested and routed rivers,

    • Completed by standing bodies (lakes, dams),

    • Related to monitoring and usage points

  • However rivers lakes, dams and points are geographical objects than can be seen, whereas catchments are concepts that need to be modelled.


River fragmentation (SEBI component): The Loire example (all known dams)

  • Historical development

  • Why not applying at the EU level?

  • Model exists and is validated,

  • Dams are placed (Eldred2)

  • Because no calculable river system!


WWTP

Sea

Dam

River

Watershed land


Production starts from reality, e.g. rivers from maps

  • What geographers see and draw is not what is needed for building reference system. Requirements are to:

  • Clarify conceptual model, mitigated by data source affordability

  • Identify objects: give usable and unique IDs

  • Group by logical consistency: set watersheds

  • Select what is important: choose homogeneous levels,

  • Relate what relates to what: connect,

  • Organise dependencies: route

  • Make it understandable and improvable: document


Conceptual modelling

  • Goals:

    • Geometrical accuracy, homogeneous and comprehensive coverage,

    • Complete topology

    • “doable” with existing data sets and free of charges

    • Stepwise model development (foreseeing Inspire implementation)

  • Designed solution

    • Operational scale 1/250k

    • Based on “functional units”: the Functional elementary catchment (FEC)

    • Made from CCM JRC, by post-processing and assimilation of other sources (ERM, Eldred32, etc.)


Concepts and production method: data source selection


Solving CCM intrinsic problems

  • CCM is a modelled catchment and network system:

    • Smallest objects possibly inaccurate because DEM resolution and ArcHydro model,

    • Being a model, it is fully connected and calculable, but objects are defined by the model, not by the envisaged uses

    • Being a model it lack gazetting

  • Being calculable, it can be improved by data processing, provided solutions are defined and implemented and recomputed in an improvement cycle

  • Completely free of charges


Solving River Basin Districts oddness

  • Districts are administrative management areas presented as if they were river basins. When used to build a river system

    • They extend over sea,

    • They don’t respect basin watershed

    • They show large “holes” (corrected in further versions)

  • Hence, adjustments are needed-> Functional RBDs


Building the FECS

  • Elementary CCM catchments are very small, numerous (~2 millions), and not directly usable because the large range of sizes (few ha to 100’s km2)

  • FEC making consisted in implementing rules of aggregation into:

    • Coastal basins and

    • Continental FECS

  • by building and populating adequate envelopes: the algorithm is based on Strahler levels, cumulated size, presence of basins and scoring criteria inside larger catchments

  • Both are then merged into a FEC layer


Clipped (limited by shoreline) international RBDs

The Functional RBDs contain the large basins

Large basins (the FEC largest envelopes)

Aggregation watershedss

  • Compute  ”Functional RBDs” from the reported RBDs:

    • Collection of FECS belonging to homogeneous basins inside the RBD

    • Difficult process because high heterogeneity of RBD delineations

  • Sub-units not ready enough yet

  • Sub-catchments made to match Functional RBDs where RBDs exist


Sub-basins (largest aggregation catchments)

FRBDs reported in violet.

Target 10,000 km2, 1470 objects

Aggregation watersheds

  • Target is to cluster FEC (mean size ~100km2) into larger watersheds (~10,000 to 35,000 km2 for example)

    • Being fully consistent with larges basins AND RBDs,

    • Having hydrological relevance

    • Which design and production are affordable

  • Design algorithm derived from FEC envelopes making, adjusted:

    • No natural envelopes,

    • Larger target size makes results more sensitive to tuning


Types of relationships exemplified: lake on the main drain, lake out of main drain, endoreic lake

Lakes and dams

  • Lakes pose serious problems because not linked to the rivers or the watersheds:

    • CCM source quite homogeneous, locally inaccurate

    • ERM source extremely heterogeneous and incomplete

  • A single data set created (~180,000 lakes) by merging and connecting to the outlet river

  • Experience suggests high difficulty in relating lakes and rivers by nodes, because conflicts between topology and geometry. River segment preferred since more operational.


Dams

  • Data sources:

    • No CCM data source,

    • ERM source heterogeneity beyond imagination and not documented (only point / multi line, no ID, no name, etc.)

    • Eldred2 data source only for large dams, not totally geolocalised.

  • Very complex processing carried out to sort out ERM dams into a single feature class and merging with Eldred (with priority to Eldred2)

    • Available end May

    • With WFD reporting, source for lake documentation


Documenting and data

  • Documents are issued with β versions of datasets

    • Report on the principles and the making of FECS, disseminated with FECs v2 β,

    • Report on the main drains disseminated with main drains v1 β

    • Report on aggregation catchments done

    • Report on lakes and dams under preparation

  • Disseminated data bases:

    • CCM Source is 18 databases for catchments, 18 for rivers and nodes, 2 summary databases (40 DB) that require 96 intermediate processing databases (reallocated, export, result and service) plus application.

    • ERM source is 2 lakes layer, 4 for dams, 2 for rivers

    • Eldred2 unique source

    • Results are in 1 database for FECs, 1 for river and nodes and 1 summary (Functional RBDs, aggregation catchments, etc), 1 for lakes and 1 for obstacles (possibly merged if possible), in CIRCA (IG: Water accounts and river fragmentation).


Achievement (16 /05/2009)


Perspectives

  • The β versions are under processing for making the « broad-brush » water accounts,

  • Sorting out the whole set of rivers by FEC minus main drain is data source for « Small rivers » assessment,

  • FECs connectivity and main routing is data source for stratified assessment of water quality, etc.


Immediate applications

  • WFD “main rivers” are defined as those draining more than 500 km2 (or any other combination).

  • The response is instantaneous:

    • And can be use as selection mask to extract data from other layers, if greater precision is required, or complementary attributes


Applications for the next SoER 2010

  • Populating data

    • Population per catchment / per cities withinn catchments

    • ECVs per catchment (done for summary data ATEAM), on going for MARS data)

  • Applications

    • Water asset accounts / water balances underway

    • Catchment stratification by drivers, altitude, etc. possible -> assessing water quality trends vs. drivers underway, (cf. 2007 methodology)

    • River fragmentation by dams underway for amphibiotic (SEBI, liaising with hydropower)

    • Small rivers issue: risks of dry-out

    • Support for WFD reporting: underway


Envisaged developments

  • Currently:

    • Seek for minor errors correction, and process a β3 version end 2009

    • Correct errors related to CCM model (e.g. karstic areas)

  • Planned

    • Integrate WFD reports to feed-back quality and inform on reporting issues

    • Stepwise gazette the rivers names and reprocess routes

    • Prepare a “CCM3” based ECRINS2 in 2011, with systematic input from geographical data at the source of hydro modelling


Pending issues (aggregation watersheds)

  • When lowering the area target, too large catchments become a problem,

  • “Too large” catchments are those that cannot be exploded by the simple algorithm used (selecting Strahler levels 6/7)

  • Supplementary algorithm to cluster differentially Strahler level 5 in underway.


Thanks for your attention

Data on CIRCA (ask for IG inscription)

mailto:philippe.crouzet@eea.europa.eu


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