philippe crouzet eea with support from walter simonazzi (etc/lusi) and eea ids staff

1WISE-GIS WG Koblenz 18-19 May 2009

Rationales for a reference GIS for Rationales for a reference GIS for Hydrosystems. The ECRINS developmentHydrosystems. The ECRINS developmentEEuropean uropean CCatchments and atchments and RIRIversvers N Network etwork SSystemystem

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


River

Sea

Watershed land

Dam

WWTP


Production starts from reality, e.g. rivers from Production starts from reality, e.g. rivers from maps 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 modellingConceptual 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: Concepts and production method: data source selectiondata source selection

Item CCM (v2.1) Geographical (ERM, etc.)

Accuracy Good for large only

Country depending

Detailed objects Erratic Accurate and comprehensive

Homogeneity Good if processed Country depending

Calculability Full (after processing)

Often not

Dissemination Free Licensed


Solving CCM intrinsic problemsSolving 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 oddnessSolving 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 FECSBuilding 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


Aggregation watershedssAggregation 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

Clipped (limited by shoreline)

international RBDs

The Functional

RBDs contain the large

basins

Large basins (the FEC largest envelopes)


Aggregation watershedsAggregation 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

Sub-basins (largest

aggregation catchments)

FRBDs reported in violet.

Target 10,000 km2, 1470

objects


Lakes and damsLakes 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.

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


DamsDams

• 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 dataDocumenting 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)Achievement (16 /05/2009)Step Concepts Preparatory

dataProduction programme

Production Populating / Gazeeting

Functional elementary catchments

Tested Tested, repeated

Tested Done (beta) Document, rainfall per FEC

Rivers Tested Tested, repeated

Tested Done (beta), headwaters to complete

Document, proposed for reporting

Functional RBDs Tested Tested, repeated

Tested done Documented, WAccounts

Aggregation catchments

Tested Tested Tested done Same as above

Lakes & dams integration

Tested Tested Tested Underway Underway

Analysing errors and maintaining

Analysed Tested Underway Correcting under analysis

Not started


PerspectivesPerspectives

• 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 applicationsImmediate 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 2010Applications 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 developmentsEnvisaged 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 Pending issues (aggregation watersheds)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 attentionThanks for your attention

Data on CIRCA (ask for IG inscription)mailto:[email protected]