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

M.C.

Evaluation of the water quality in the Enxoé river –

Eutrophization risk?

Collecting regulary water samples & using a automatic sampling station

Streamlets RE and VV supply the Enxoé watershed

How Why

•Monotoring water from Ribeira do Monotoring water from Ribeira do Enxoé (RE) Enxoé (RE) & Vale de Vargo (VV)& Vale de Vargo (VV)

•Use a Piper Diagram to classified the types of waters

•Use a statistic tool PCA (Principal Component Analysis) to analyse physico-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.

IntroductionIntroduction

General characteristics

Enxoé River during dry season

•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.

Material & Methods Data Presentation Conclusions

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.

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.

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)

IntroductionIntroduction Material & Methods Data Presentation Conclusions

Catchment Enxoé Main catchment Guadiana Area (km2) 60 Altitude max-min (m) 175-300 Dominant geology Granites, Calcareous and Schists Pedology Luvisols, Cambisols and Calcisols (FAO,

WRB 2006) Dominant and secondary soil occupation

Dominant: Olive groves and Oak tree mediterranean woodland “montado” Secondary: winter crops

Rainfall (mm per year) 500 Valley type Gentle ondulating relief River bed length (km) 9 (from the source to Enxoé dam) Hydrological management

Vegetation Olive trees, Oak trees mediterranean woodland

Mean annual discharge (m3 s-1)

Not measured

Mean discharge in low water period (m3 s-1)

Not measured

Bi-annual flood discharge

Not measured

Hydrological regime Pluvial Catchment population 1000 inhabitants Main cities 1 village Vale do Vargo Waste water treatment station

Yes, but the waste waters are pumped outside Enxoé catchment

Typical Landscape

IntroductionIntroduction Material & Methods Data Presentation Conclusions

Introduction Material & Methods Data PresentationData Presentation Conclusions

•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.

Eutrophication

IntroductionIntroduction Material & Methods Data Presentation Conclusions

• FertilizersFertilizers Fertilizers 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 WasteAnimal Waste Phosphate runoff can be an issue in waters near cattle feedlots, farms, dairies, and barnyards.

• Wastewater and Septic System Effluent 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 Detergents Orthophosphates and certain polyphosphates are major constituents of many commercial cleaning preparations

• Forest Fires Forest Fires Forest fires can cause soil erosion, which will release phosphorus bound to soil particles.

• Synthetic Materials 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.

Factors that can Influence Phosphorus Concentrations in Enxoé Catchment

IntroductionIntroduction Material & Methods Data Presentation Conclusions

Map of Enxoé Catchment

IntroductionIntroduction Material & Methods Data Presentation Conclusions

Monitoring Sites – Ribeira do Enxoé & Vale de Vargo

Sampling and Chemical Analysis (Jan 2010- May 2011)

Photos of different spots of sampling

Samples collect in triplicate

VVRE

REVV

IntroductionIntroduction Material & Methods Data Presentation Conclusions

Automatic Sampling Station

Introduction Material & MethodsMaterial & Methods Data Presentation Conclusions

Parameters Observations

pH •The normal value of pH for sweet waters is between 4 and 9.

Chlorides The sudden change of Chlorine concentrarion in waters is a contamination indicator. The average concentration shoud be comprise between 10 -50 ppm.

Carbonates and hidrogenocarbonates

The hidrogenocarbonate concentration in sweet waters shoud be comprise betwwen 50 e 350 ppm. The carbonates concentration is usually smaller (50ppm).

TSS - total suspended solids

The average values should be situates between 75-300 ppm.

EC- electrical conductivity

Values bigger 2000 microhms/cm should not be use in agricultural

Total P Total phosphorus (TP) is a measure of all the forms of phosphorus, dissolved or particulate, that are found in a sample.

Orthophosphate Orthophosphate is the most stable kind of phosphate, and is the form used by plantstotal phosphate should not exceed 0.05 mg/L (as phosphorus) in a stream at a point where it enters a lake or reservoir, and should not exceed 0.1 mg/L in streams that do not discharge directly into lakes or reservoirs

Introduction Material & MethodsMaterial & Methods Data Presentation Conclusions

Parameters Observations

Ammonium Should not exceeed 10 ppm in waters

Nitrate Should not exceeed 50 ppm in waters

Iron Rivers contain approximately 0.5-1 ppm of iron, and groundwater contains 100 ppm. Drinking water may not contain more than 200 ppb of ironFe+3 + PO4

-3 FePO4 (solid)

Calcium The concentration of the Calcium ion in water should vary between 10-250ppm, but in some cases can achieved 600 ppm.

Mangnesium The concentration of the Magnesium ion in water should vary between 10-100ppm, but in some cases can achieved 600 ppm

Sodium The concentration of the Sodium ion in freshwater should vary between 10-150 ppm, but in some cases can achieved 600 ppm. If the value is superior to 10 ppm it is not not adequate to irrigation waters.

Potassium Rivers generally contains about 2-3 ppm potassium

Dissolved Organic Carbon (DOC)

Concentrations of DOC in undisturbed watersheds generally range from approximately 1 to 20 mg/L carbon

Introduction Material & Methods Data PresentationData Presentation Conclusions

Vale de Vargos

Ribeira do Enxoé

Waters collected in ER and VV are identical, being characterized as calcium or magnesium bicarbonate waters.

Diagrama de Piper

Introduction Material & Methods DataData PresentationPresentation Conclusions

Vale de VargosRibeira do Enxoé

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

Introduction Material & MethodsMaterial & Methods Data Presentation Conclusions

•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.

Introduction Material & Methods Data PresentationData Presentation Conclusions

Rib

eir

a d

o E

nxoé

Rib

eir

a d

o E

nxoé

Projection of the variables on the factor-plane ( 1 x 2)

Active

pH

EC TSS

ALC POC

DOC

Norg

NO3

NH4

NTotal dis

P total

P-PO4

Cl

Ca

Mg Na

K

F e

-1,0 -0,5 0,0 0,5 1,0

Factor 1 : 41,50%

-1,0

-0,5

0,0

0,5

1,0

Factor 2 : 14,98%

1º trimester

Factor 1 Factor 2

pH 0,749504

EC 0,906646

TSS -0,845190

ALC 0,715074

POC -0,862224

DOC 0,708488

Norg

NO3 0,648458

NH4

Ntot diss 0,768605

P total -

P-PO4

Cl

Ca 0,802576

Mg 0,771614

Na 0,754235

K

Fe -0,849477

Projection of the variables on the factor-plane ( 1 x 2)

Active

pH CE

SST

ALC.

COP

COD

Norg. NO3

NH4

NTotal dissol

P total P-PO4

Cl

Ca Mg

Na K

Fe

-1,0 -0,5 0,0 0,5 1,0

Factor 1 : 51,36%

-1,0

-0,5

0,0

0,5

1,0

Fa

cto

r 2

: 1

7,9

1%

Vale

de V

arg

os

Vale

de V

arg

os

Factor 1 Factor 2

pH 0,790803

EC 0,951348

TSS -0,953656

ALC 0,803283

POC -0,947869

DOC 0,847739

Norg

NO3

NH4

Ntot diss 0,840559

P total

P-PO4

Cl 0,845859

Ca 0,951401

Mg 0,936189

Na 0,888367

K

Fe -0,917555

Introduction Material & Methods Data PresentationData Presentation Conclusions

Rib

eir

a d

o E

nxoé

Rib

eir

a d

o E

nxoé Projection of the variables on the factor-plane ( 1 x 2)

Active

pH

EC

TSS

ALC

POC

DOC

Norg

NO3

NH4

NTotal dis

P total

P-PO4

Cl

Ca

Mg

Na

K

F e

-1,0 -0,5 0,0 0,5 1,0

Factor 1 : 35,13%

-1,0

-0,5

0,0

0,5

1,0

Factor 2 : 18,99%

2º trimester

Factor 1 Factor 2

pH 0,835795

EC -0,840030

TSS

ALC -0,788159

POC

DOC

Norg -0,705111

NO3

NH4 -0,716897

Ntot diss 0,801144

P total -0,743783

P-PO4 -0,764558

Cl 0,767565

Ca

Mg 0,752577

Na

K -0,859279

Fe -0,798025

Projection of the variables on the factor-plane ( 1 x 2)

Active

pH

EC

SST

ALC.

POC

DOC

Norg.

NO3

NH4 NTot. dissol

P total

P-PO4

Cl

Ca

Mg

Na

K

Fe

-1,0 -0,5 0,0 0,5 1,0

Factor 1 : 49,84%

-1,0

-0,5

0,0

0,5

1,0

Fa

cto

r 2 : 1

6,5

8%

Vale

de V

arg

os

Vale

de V

arg

os

Factor 1 Factor 2

pH 0,940278

EC -0,872873

TSS 0,923134

ALC

POC

DOC

Norg -0,771963

NO3

NH4 -0,777218

Ntot diss 0,874679

P total -0,851823

P-PO4 -0,915901

Cl

Ca -0,778568

Mg -0,975825

Na

K -0,958703

Fe -0,930680

Introduction Material & Methods Data PresentationData Presentation ConclusionsR

ibeir

a d

o E

nxoé

Rib

eir

a d

o E

nxoé

Projection of the variables on the factor-plane ( 1 x 2)

Active

pH

EC TSS

ALC POC

DOC

Norg

NO3

NH4

NTotal dis

P total

P-PO4

Cl

Ca

Mg Na

K

F e

-1,0 -0,5 0,0 0,5 1,0

Factor 1 : 41,50%

-1,0

-0,5

0,0

0,5

1,0

Factor 2 : 14,98%

3º trimester

Factor 1 Factor 2

pH 0,749504

EC 0,906646

TSS -0,845190

ALC 0,715074

POC -0,862224

DOC 0,708488

Norg

NO3 0,648458

NH4

Ntot diss 0,768605

P total -

P-PO4

Cl

Ca 0,802576

Mg 0,771614

Na 0,754235

K

Fe -0,849477

Projection of the variables on the factor-plane ( 1 x 2)

Active

pH

EC

TSS

ALC.

POC

DOC

Norg.

NO3

NH4

NTot. dissol

P total

P-PO4

Cl

Ca

Mg

Na K

Fe

-1,0 -0,5 0,0 0,5 1,0

Factor 1 : 37,26%

-1,0

-0,5

0,0

0,5

1,0

Fa

cto

r 2 : 1

8,3

7%

Vale

de V

arg

oV

ale

de V

arg

o

Factor 1 Factor 2

pH

EC 0,876281

TSS

ALC 0,907233

POC

DOC

Norg 0,790008

NO3 -0,750137

NH4

Ntot diss 0,746716

P total

P-PO4

Cl 0,961097

Ca

Mg 0,935107

Na 0,947262

K

Fe

Introduction Material & Methods Data Presentation ConclusionsConclusions

•1st trimester - Results were 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 - Results were 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 –Results were identical in both places PC1 loading superiors then 80% for EC, Mg, Na e Cl.• PC2 (Norg and Ntdiss).

Observed identical results in RE and VV

•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.