Prazeres A., Rodrigues S., Tavares J., Morgado O., Castelo-Branco M.A., Gonçalves M.C.

1. Evaluation of the water quality in the Enxoé river – Eutrophization risk? Prazeres A., Rodrigues S., Tavares J., Morgado O., Castelo-Branco M.A., Gonçalves M.C.

2. Monotoringwaterfrom Ribeira do Enxoé (RE) • & Vale de Vargo(VV) How Why Collectingregularywatersamples & using a automatic sampling station Streamlets RE and VV supply the Enxoé watershed • Use a PiperDiagram to classifiedthetypesofwaters • Use a statistictool PCA (Principal ComponentAnalysis) to analysephysico-chemical parameters. • PCA was applied to the normalized data to compare the compositional patterns between the analyzed water samples and to identify the factors that influence each one of the streamlets.

3. Introduction Material & Methods Data Presentation Conclusions General characteristics • The Enxoé river basin is included in the basin of the Guadiana River and is located in Serpa Municipality, in Beja District. • The study area, corresponding to the Enxoé catchment area of the reservoir, has 6080 ha, and an average altitude of about 200 m. • The study site of Enxoé river is located in a rural area, near the small village of Vale do Vargo, at approximately 40 km from Beja city. Enxoé River during dry season

4. Introduction Material & Methods Data Presentation Conclusions • Hydro-climatic conditions • The hydrological regime of the catchment is pluvial and is characterized by a strong interannual and intrannual variation of the discharges. • The Enxoé basin presents drought mediterranean characteristics, with hot summers, high insolation and high evapotranspiration. • The annual average precipitation in the basin is about 500 mm, being the interannual distribution of precipitation extremely irregular with more than 80% of the annual total of the precipitation concentrated between October and April. During summer time Enxoé river frequently presents no flow. • The annual average temperature is about 16°C. The annual reference evapotranspiration varies between 1200 mm and 1300 mm. Land use The dominant land uses in Enxoé basin are olive groves (2740 ha), and agro-forestry of holm-oak (2005 ha). Winter crops, maize and pastures (1050 ha), water (205 ha) and urban area (80 ha) are also important land uses to consider. Soils characteristics In the Enxoé catchment, the dominant soils are Luvisols covering 45% (Calcic Luvisols 13%), Cambisols 30%, and Calcisols 15% of the area. (FAO, WRB 2006)

5. Introduction Material & Methods Data Presentation Conclusions Typical Landscape

6. Introduction Material&Methods Data Presentation Conclusions Eutrophication • Phosphates are not toxic to people or animals unless they are present in very high levels. Digestive problems could occur from extremely high levels of phosphate. • In freshwater lakes and rivers, phosphorus is often found to be the growth-limiting nutrient, because it occurs in the least amount relative to the needs of plants. • If excessive amounts of phosphorus and nitrogen are added to the water, algae and aquatic plants can be produced in large quantities. When these algae die, bacteria decompose them, and use up oxygen.

7. Introduction Material & Methods Data Presentation Conclusions Factors that can Influence Phosphorus Concentrations in Enxoé Catchment • FertilizersFertilizers generally contain phosphorus in the form of orthophosphate. Phosphate is not very mobile in soil; it tends to remain attached to solid particles rather than dissolving in water. If too much fertilizer is applied, the phosphates are carried into surface waters with storm runoff. Soil erosion of fertilized fields and lawns can also carry a considerable amount of particulate phosphate to streams. • Animal WastePhosphate runoff can be an issue in waters near cattle feedlots, farms, dairies, and barnyards. • Wastewater and Septic System Effluent Organic phosphates are formed primarily by biological processes. They are contributed to sewage by body waste and food residues • Detergents Orthophosphates and certain polyphosphates are major constituents of many commercial cleaning preparations • Forest Fires Forest fires can cause soil erosion, which will release phosphorus bound to soil particles. • Synthetic Materials Organophosphates are commonly used as construction materials, flame retardant and plasticizers. Reduced forms of phosphorus are present in certain synthetic organic chemicals, including some that are used in insecticides.

8. Material & Methods Introduction Data Presentation Conclusions Map of Enxoé Catchment

9. Material & Methods Introduction Data Presentation Conclusions Monitoring Sites – Ribeira do Enxoé & Vale de Vargo Sampling and Chemical Analysis (Jan 2010- May 2011) RE VV VV RE Photos of different spots of sampling Samples collect in triplicate

10. Material & Methods Introduction Data Presentation Conclusions Automatic Sampling Station

11. Material & Methods Introduction Data Presentation Conclusions

12. Material & Methods Introduction Data Presentation Conclusions

13. Data Presentation Introduction Conclusions Material & Methods Diagrama de Piper Vale de Vargos Ribeira do Enxoé Waters collected in ER and VV are identical, being characterized as calcium or magnesium bicarbonate waters.

14. DataPresentation Introduction Conclusions Material & Methods Vale de Vargos Ribeira do Enxoé

15. Material & Methods Introduction Data Presentation Conclusions • PCA-Principal Component Analysis • Given a data set described by a set of numerical variables {x1, x2 , ..., xp}, the goal of Principal Components Analysis is to describe this data set with a smaller set of new, synthetic variables. These variables will be linear combinations of the original variables, and are called Principal Components. • Quite generally, reducing the number of variables used to describe data will lead to some loss of information. PCA operates in a way that makes this loss minimal, in a sense that will be given a precise meaning. • Therefore, PCA may be regarded as a dimensionality reduction technique. SOURCE-www.princeton.edu/~aspremon/OptSPCA.pdf • The year was divided in three trimesters (Jan-Feb-Mar, Apr-May-Jun, and Sept-Oct-Nov) and for each trimester was carried out, a Principal Components Analysis (PCA). Using this analysis it was possible to reduce the number of parameters determinant of the behaviour of water quality. • PCA evolved 3 PCs with eigenvalues >1 explaining about 80% total variance.

16. Data Presentation Introduction Conclusions Material&Methods 1º trimester Vale de Vargos Ribeira do Enxoé

17. Data Presentation Introduction Conclusions Material&Methods 2º trimester Vale de Vargos Ribeira do Enxoé

18. Data Presentation Introduction Conclusions Material&Methods 3ºtrimester Vale de Vargo Ribeira do Enxoé

19. Introduction Conclusions Material&Methods Data Presentation • 1st trimester - Resultswere identical in both places PC1 showed high positive loading (>0,70) on EC, Ca, Mg, Na, and Alc, as well as on Fe, POC and the TSS. • PC2 (DOC and Ntdiss) contributes on average with 15.5% of the total variance. • 2nd trimester - Resultswere identical in both places PC 1accounts for 35.5% and 49.4% respectively of the total variance with high positive loadings between EC, NH4, Norg, Ptotal, P-PO4, K, Fe. • PC2 accounts for 18.9% and 16.6% of total variance, showed moderate loadings between pH and Ntdiss. • 3rd trimester –Resultswere identical in both places PC1 loading superiors then 80% for EC, Mg, Na e Cl. • PC2 (Norg and Ntdiss). • P is the most important parameter in the eutrophization control. • Only in the 2nd trimester its influence was significant. • This was probably owed to stream change due to precipitation. Observed identical results in RE and VV