1. Patterns of hydrological alteration in the Iberian Peninsula
Francisco J. Peñas, Oscar Belmar & José Barquín
DO RESERVOIRS WITH A SIMILAR OPERATION RULE PRODUCE ALWAYS THE SAME EFFECT?
Patterns of hydrological alteration in the Iberian Peninsula
Francisco J. Peñas, Belmar, O. &. & Barquín, J.
Environmental Hydraulics Institute “IH Cantabria”, University of Cantabria.

2. Background: Project HYDRA
HYDRA focuses on the study of how river ecosystems are affected by HYDROLOGICAL ALTERATION from dam operation and land use changes and will explore how these effects are translated to river service provisioning.

3. Background: Project HYDRA
Account for different levels of biological organization
Using a Virtual Watershed approach:
Order, model and communicate environmental information
Assess of the Hydrological Alteration
new tools for Ecosystem Service Valuation such as ARIES

4. REGIONAL Hydrological alteration assessment Case by case studies
Introduction
The assessment of Hydrological alteration
REGIONAL Hydrological alteration assessment
Case by case
studies
POST-DAM
PRE-DAM
♦ Not available data
Hydrological classifications
Peñas et al., Ecological indicators
♦ Natural hydrology
of the river
♦ Use of the reservoir
Hydrological Index A
Before
After
% of change

5. Objectives The main objective of this work is to:
Infer a general insight of the hydrological alteration in the northern half of the Iberian peninsula.
Analyse the variability of the hydrological alteration according to the natural hydrology of the river and the size and main use of the reservoirs
Hydrological classification
Natural flow regimes
Altered flow series
Downstream reservoirs
Analyse deviation from natural condition

6. Study area and initial data Study area and hydrological data
Methods
Study area and initial data
Cantábrico
Galicia
Costa
Miño-Sil
Cataluña
Duero
Ebro
● Series of daily mean flow (Gauge stations)
● Criteria to select unmodified gauges
Visual examination of hydrographs
Elimination of years with gaps > 30 days
Retention of gauges with records longer than 7 years for the period
Study area and hydrological data

7. Study area and initial data ENVIRONMENTAL INFORMATION
Methods
Study area and initial data
FLUVIAL NETWORK
Climate
Geology
Land Cover & Land Uses
ENVIRONMENTAL INFORMATION

8. Study area and initial data HYDROLOGICAL INFORMATION
Methods
Study area and initial data
HYDROLOGICAL INFORMATION
679 Gauge stations
(mean daily flow)

9. Study area and initial data HYDROLOGICAL INFORMATION
Methods
Study area and initial data
HYDROLOGICAL INFORMATION
Hydrological classification
392 unmodified flow records
679 Gauge stations
(mean daily flow)
Hydrological alteration analysis
287 altered flow records

10. Study area and initial data HYDROLOGICAL INFORMATION
Methods
Study area and initial data
HYDROLOGICAL INFORMATION
392 unmodified flow records
679 Gauge stations
(mean daily flow)
Visual examination of hydrographs
Gaps < 30 days
Records longer than 7 years
Period
221 Gauge stations

11. Study area and initial data HYDROLOGICAL INFORMATION
Methods
Study area and initial data
HYDROLOGICAL INFORMATION
279 reservoirs (>1 hm3)
679 Gauge stations
(mean daily flow)
287 altered flow records

12. Study area and initial data HYDROLOGICAL INFORMATION
Methods
Study area and initial data
HYDROLOGICAL INFORMATION
Hydropower (HP; 16)
Irrigation (IR; 16)
Water supply (WS,7)
Industrial (IN; 1)
HP/IR (12)
HP/WS (7)
IR/WS (3)
HP/IR/WS (4)
679 Gauge stations
(mean daily flow)
66 Gauge stations
287 altered flow records

13. Hydrological classification of the fluvial network:
Methods
Hydrological classification of the fluvial network:
PREDCIT-THEN-CLASSIFY
PC1
PC2
ML30
ML90
75per
sdMH7
sdMH30
nHPulse
Frequency
Magnitude
Duration
Timing
Rate of change
Mean flows
Floods/ spates
Droughts 84
Hydrologic
Indices
221 Natural flow series
Predicted PCs
(Network)
PCs
(gauges)
Environmental Data
Hydrologic Classes
Fitted Model
(Random Forest)
Clustering
Environmental data

14. Hydrological alteration assessment
Methods
Hydrological alteration assessment 84
Hydrologic
Indices
PCs values of altered gauges
(natural PCA)
PCs values of natural gauges
66 Altered flow series
PC2
PC1

15. Hydrological classification of the fluvial network
Results
Hydrological classification of the fluvial network
PC1 – Magnitude & duration of low flows (+)
PC4 – Magnitude spring flows (+) / winter flows (-)
PC2 – Variability Magnitude & duration of high flows (+) / number of high flow pulses (-)
PC5 - Magnitude spring flow & timing max flows (+) / Variability summer flows (-)
PC3 – Variability of mean flows (+) / Magnitude & duration of high flows (-)
PC6 – Variability of high flows events frequency
9-Class level classification

16. Var. of high flows frequency.
Results
Hydrological Class 1
Hydrological Class 1
PC1 vs PC2
PC1 vs PC2
PC3 vs PC4
PC4 vs PC5
Var. high
flows mag.
Spring flow timing max.
Spring flow
n high pulses.
Var. summer flows
Winter flows
High flows mag.
Var. of high flows frequency.
Low flows mag.
Natural flow HP IR WS IN
HP/IR HP IR WS IN
HP/IR
HP/WS
IR/WS
HP/IR/WS

17. Var. of high flows frequency.
Results
Hydrological Class 2
PC1 vs PC2
PC3 vs PC4
PC4 vs PC5
Var. high
flows mag.
Spring flow timing max.
Spring flow
n high pulses.
Var. summer flows
Winter flows
Low flows mag.
High flows mag.
Var. of high flows frequency.
Natural flow HP
HP/IR
HP/WS
IR/WS
HP/IR/WS HP IR WS IN
HP/IR
HP/WS
IR/WS
HP/IR/WS

18. Var. of high flows frequency.
Results
Hydrological Class 3
PC1 vs PC2
PC3 vs PC4
PC4 vs PC5
Var. high
flows mag.
Spring flow timing max.
Spring flow
n high pulses.
Var. summer flows
Winter flows
Low flows mag.
High flows mag.
Var. of high flows frequency.
Natural flow HP IR WS
HP/IR
HP/WS HP IR WS IN
HP/IR
HP/WS
IR/WS
HP/IR/WS

19. Var. of high flows frequency.
Results
Hydrological Class 4
PC1 vs PC2
PC3 vs PC4
PC4 vs PC5
Var. high
flows mag.
Spring flow timing max.
Spring flow
n high pulses.
Var. summer flows
Winter flows
High flows mag.
Var. of high flows frequency.
Low flows mag.
Natural flow HP IR WS
HP/IR/WS HP IR WS IN
HP/IR
HP/WS
IR/WS
HP/IR/WS

20. Var. of high flows frequency.
Results
Hydrological Class 5
PC1 vs PC2
PC3 vs PC4
PC4 vs PC5
Var. high
flows mag.
Spring flow timing max.
Spring flow
n high pulses.
Var. summer flows
Winter flows
High flows mag.
Var. of high flows frequency.
Low flows mag.
Natural flow IR WS
HP/WS
IR/WS
HP/IR/WS HP IN
HP/IR
HP/WS
IR/WS
HP/IR/WS

21. Var. of high flows frequency.
Results
Hydrological Class 7
PC1 vs PC2
PC3 vs PC4
PC4 vs PC5
Var. high
flows mag.
Spring flow timing max.
Spring flow
n high pulses.
Var. summer flows
Winter flows
Low flows mag.
High flows mag.
Var. of high flows frequency.
Natural flow IR
HP/WS HP WS IN
HP/IR
HP/WS
IR/WS
HP/IR/WS

22. Var. of high flows frequency.
Results
Hydrological Class 9
PC1 vs PC2
PC3 vs PC4
PC4 vs PC5
Var. high
flows mag.
Spring flow timing max.
Spring flow
n high pulses.
Var. summer flows
Winter flows
Low flows mag.
High flows mag.
Var. of high flows frequency.
Natural flow IR
HP/IR HP WS IN
HP/WS
IR/WS
HP/IR/WS

23. Conclusions
Both the hydrological nature of the river and the activity influence the magnitude, the direction and the hydrological aspect altered by the reservoir.
The use of hydrological classifications to assess the hydrological alteration at large spatial scales seems to be a useful tool
The size of the reservoirs did not produced a clear and unequivocal effect on hydrological alteration
This study must be completed with a larger number of altered series (e.g. flows released from reservoirs database)

24. Thanks for
your attention!!