Catalonia is a small region, managed by an autonomous government (depending from Spain), and placed in NE. Spain, next to Mediterranean sea.

Transcription

1 Characterization of the river basin according to the WFD The Catalan Basins, a case of small Mediterranean water district Planning Department c/ Provença, Barcelona Introduction to Catalonia region Catalonia is a small region, managed by an autonomous government (depending from Spain), and placed in NE. Spain, next to Mediterranean sea. Catalonia (31,896 Km2) have two different water districts: Catalan Internal Basins, which is composed by several small basins that drain to the Mediterranean sea, and completely placed into Catalonia (16,628 Km2-52 % of the Catalonia territory). Catalan Interregional Basins, that form part of the Ebro Basin, and a small part of the Garona basin (which drain to the Atlantic ocean through France). (15,268 Km2-48 % of the Catalonia territory). The Catalan Internal Basins have a group of small watersheds that drain directly to de Mediterranean sea. These basins make up a water management unit which is under the authority of the Autonomous Government of Catalonia (), and managed by the. In Spain, the river basins units (like Ebro watershed, Segura etc.) are managed by state bodies called Confederaciones Hidrograficas which are under the authority of the Central Government. But the Catalan Internal Basins, as Basque Internal Basins (in the north of Spain), are managed by respectably Autonomous Regional Governments (Catalonia and Euskadi). Competences of the have full competences in the Catalan Internal Basins: Elaboration of Plans and Programmes Their follow-up Control of water resources, their quality and quantity Give permits Planning (implementation of WFD) 4th June

2 Inter-regional Basins The only have competences in management & control For this raison we are working making river basin characterization only in the Catalan Internal Basins, which we have competences to planning. Characteristics of river basin district This must be completed at the least four years after the day of publication of WFD (22 Dec. 2004). Reviewed at the least in 22 December of 2013, and every six years thereafter. In this moment (in the ), we are working to define the different water bodies in our river basin district which we have competences (the Catalan Internal Basins). Firstly, we have to define the boundaries of the river basin district (in our case, the Catalan Internal Basins), including the coastal waters influenced by our rivers. We use the Digital Terrain Model (DTM) to define the terrestrial part of the river basin district (using GIS tools), we also have to include the groundwater, and finally we define the part of costal waters that are influenced by the river basin flow. Secondly, we should define the Categories into the river basin district. Now we are working defining: Rivers (with drainage area up to 10 km 2 ) Lakes (up to 0,005 km 2 ) Shallow lakes (we considerate this as a new category different to lakes) Coastal waters Heavily modified waters (reservoirs, rivers with high morphometric human alterations ) In our River Basin District, we don t have: Transitional water (we do not have big rivers with an estuary the Ebro river is not in the Catalan Internal Basins) Artificial waters (we do not have big channels ) Into the water categories, we sub-divide it in water body types, and finally we define de water bodies as a part of water body type. The final Water body defined should be a coherent sub-unit in the river basin district, into a water category and water type, to which the environmental objectives of the Directive must apply. An example: Making river types The Water Framework Directive (WFD) proposes the characterization of river types through two regionalization systems: A and B (Annex II of the WFD). For this reason, we have some questions: What System do we have to use?. What System is better? To answer this, we have compared Systems A and B, proposed by the WFD, in the Catalan Water District, to define river types. 4th June

3 Using System A As stipulated in Annex II of the WFD, and using the 25 pre-established ecoregions described in its Annex XI, we first determined the ecoregions in the Catalan Water District. This district hold in this case two, the Pyrenean and Iberic-Macaronesian regions. If we use only the Annex XI, the limit between the two ecoregions is not clear. We have defined, at more detailed scale, the two Ecoregions (Pyrenees and Iberic-Macaronesian) using morphological, climatic, geological and biogeographical criteria from numerous local references. Secondly, we established the river types for each two regions using the three main criteria set out by the WFD. Three coverages using Arc/Info GIS were built using the river definition criteria for System A: altitude, surface area of basin, and geological surface. 4th June

4 Pyrenees and Iberic-Macaronesian Ecoregions. Boundaries based on morphological and climatic criteria and bio-geographical distribution of natural vegetation coverage Classification by surface area of the Catalan Water District. The three river sizes are shown according to the regional classification of System A of the WFD Classification by simplified surface geology of Catalan Water District. The two types of geological structure found in Catalonia are shown according to the regional classification of System A of the WFD Classification by altitude of Catalan Water District. The three altitudes types, according to the regional classification of System A of the WFD, are shown Crossing these coverages we obtained a classification of river types: Ecoregions using System A Types by altitude Types by surface area of basin Types by surface geology Total types by ecoregion Pyrenees 2 (3) 2 (4) 2 (3) 8 (36) Iberic-Macaronesian 3 (3) 3 (4) 2 (3) 18 (36) Total river types 26 (72) The number of categories are shown for the three main descriptors (altitude, size typology, and geology). Numbers in brackets show the potential number of overall categories using System A. A maximum of 72 potential river types were identified in the Catalan Water District, 36 for each region. However, not all the categories are present in the two regions. The Pyrenean region does not have river systems below 200 m of altitude, nor the Large (>1,000 Km 2 ) and Very Large (>10,000 Km 2 ) surface area categories. Furthermore, neither of the two regions show a significant percentage for the geological classification of organic. Of the 72 potential river types possible in System A only 26 were effectively present, 8 in the Pyrenees and 18 in the Iberic-Macaronesian regions. 4th June

5 Finally, a total of 26 possible river types was defined (using System A) over 16,628 km 2 of the water district. This System give a mosaic of territorial units of great diversity. Using System B System B (Annex II of the WFD) proposes a group of descriptors to be analysed: 5 Obligatory factors A group of 15 Optional factors We used the obligatory factors, plus several optional ones for which information was already available, and some descriptors that could provide useful information, especially given the peculiarities of our river basin district (placed in the Mediterranean zone: as flow variability index, or annual runoff coefficient). Site-specific Basin Group of variables Hydrological Morphological Geological Climatic Factors Annual discharge Annual runoff coefficient Dry-period index Altitude Mean water slope Surface drainage area River order River fork rate Valley shape Surface carbonate geology Surface siliceous geology Surface carbonate and sulphate evaporites Surface evaporite geology Surface evaporite with chlorines Surface sedimentary geology of mixed origin Mean air temperature Precipitation The variables considered obligatory by the WFD are shown in bold, those considered optional are in italics and the rest are other variables introduced. We used a multivariant method to establish the river types. To identify variables with similar characteristics, a Pearson correlation analysis was performed into each group according to the origin. A correlation coefficient over 0.8 (p<0.05) was used as a criterion to reduce the number of variables in each group. For further analysis, only one was kept. Next, to summarize environmental complexity and to explain the spatial variability we performed a Principal Components Analysis (PCA). PCA is a ordination method that consists of plotting objectpoints along axes that represent an ordered relationship between several descriptors. We used the principal axis for new variables summarising and maximizing differences between the analysed variables. We selected the PCA scores from each site (the projection of each sampling site on the principal axis) as new variables An example of Principal Components Analysis using the Hydrological data is showed: 4th June

6 In the left we show the spatial distribution in the Catalan Water District of the first (above) and second (below) axis of PCA. In the right we show the PCA plot distribution of sites analysed. The same procedure was applied to the other groups of variables. This procedure determines the gradients along which the sites vary with respect to each group of variables. Seven PCA axes, that explained a high percentage of variation and could be interpreted as a function of the most important variables, were selected to define a group of sites using a cluster analysis (the river types). The river regions were clearly defined in space, were environmentally homogenous, and therefore had similar hydrological and morphological conditions, and presumably very similar biological communities Given the heterogeneous conditions of the Catalan Water District, and the availability of reliable detailed data, we took the level of distinction even further than that contemplated by the WFD. Thus, we distinguished the River types, which may be useful for comparison at European scale, from Sub-types of river management, which are operational at local scale, such as the small and heterogeneous Catalan Water District. River types Sub-types of river management 1. Wet mountains 1a. Siliceous wet mountains 1b. Calcareous wet mountains 2. Mediterranean climate mountains 2a. Siliceous Mediterranean climate mountains 2b. Calcareous Mediterranean climate mountains 2c. Mediterranean climate mountains with high discharge 3. Dry Mediterranean climatic area 3a. Lowlands Mediterranean climate zone 3b. Siliceous dry Mediterranean climate zone 3c. Karstic feed rivers 4. Large watercourses 4a. Large watercourses 5. Coastal streams 5a. Coastal streams 4th June

7 Using the river types and sub-types of river management, we can establish the reference sites for every one using the biological indicators or metrics, and the water bodies into this types. Conclusions comparing Systems A and B Using System A. The differentiation of 26 river types, within the Catalan Water District, makes the measurement of the ecological status of the river systems complex and expensive for the Catalan Water District given the many river types to be analysed Using System B. This methodology allows select variables in function of their similarity and the way in which they represent spatial heterogeneity conditions according to the hydrological, morphological, geological and climatic conditions. We propose the System B (using a multivariant method) to synthesize all environmental descriptors and to define river types 4th June

8 Summary Define the River Basin District boundary Boundaries between watersheds Define the coastal waters with river influences Establish de water categories Rivers Lakes (shallow lakes) Coastal waters Transitional waters Heavily modified and artificial waters Groundwater Split in different types We can use Systems A or B Define the Water Bodies Using anthropogenic criteria 4th June