hydropower production and fish habitat suitability

W12 Water resources management and the competition/balance between humans and ecosystems (eco-hydrology) CWed, 12 Jul, 08:30–12:20 / Room Woodrooms IAHS SCIENTIFIC ASSEMBLY 201710–14 JULY 2017PORT ELIZABETH, SOUTH AFRICA

HYDROPOWER PRODUCTION AND FISH HABITAT SUITABILITY: IMPACT AND EFFECTIVENESS OF ENVIRONMENTAL FLOW PRESCRIPTIONS Serena Ceola1, Alessio Pugliese1, Giorgio Galeati2, Attilio Castellarin1 1

Department DICAM, University of Bologna, Bologna, Italy 2 Water Resources Engineer, Padova, Italy

Ceola et al. - Hydropower prod. vs. fish habitat suitability: impact and effectiveness of e-flows

Overview & Motivation Anthropogenic alteration of natural flow regime for hydropower production can significantly impact processes and functions associated with fluvial ecosystems. In order to preserve the fluvial habitat downstream of dams and diversion structures, environmental flows (e-flows) are commonly defined and enforced. e-flows generally have an empirical nature, and are based on hydrological variables (e.g. flow percentiles), which seldom rely on site-specific studies and may not be representative of local ecological and hydraulic conditions. Tharme, R.E., (2003), A global perspective on environmental flow assessment: emerging trends in the development and application of environmental flow methodologies for rivers. River Research and Applications, 19 (5–6), 397–441

e-flows should instead incorporate the ecological requirements of different biological communities and reflect the natural temporal variability of flows. Arthington, A.H., et al., (2006), The challenge of providing environmental flow rules to sustain river ecosystems. Ecological Applications, 16, 1311–1318. Ceola, S., et al., (2013), Hydrologic variability affects invertebrate grazing on phototrophic biofilms in stream microcosms. PLoS ONE, 8(4), e60629.


Overview & Motivation GOAL: quantitative analysis on the effectiveness of alternative e-flow scenarios and their impact on hydropower production and fish habitat suitability Q [m3/s]

HYDROPOWER PRODUCTION ESTIMATION vs SEAS SEAS 1 2

SEAS 3

SEAS 4

NFR- Natural flow regime SCENARIO 1 SCENARIO 2

SEAS 1

Time [days]

HABITAT SUITABILITY ASSESSMENT

Chub Barb Leuciscus Barbus barbus plebejus cephalus cabeda


Case Study

Potenza and Chienti river basins Marche administrative district in Central Italy

Chienti

Potenza

Basin

• 14 hydropower production sites:

10 RUN-OF-THE-RIVER (ROR) 4 STORAGE (DAM)

Hydropower site Pioraco

ROR

Castelraimondo

ROR

San Severino

ROR

Montefranco

ROR

Villa Potenza

ROR

Fontenoce

ROR

Montelupone

ROR

Fiastrone

ROR

Fiastra

DAM

Polverina

DAM

Borgiano

DAM

S. Maria

DAM

Città di Macerata

ROR

S. Maria Apparente

ROR

• Hydropower Production (HPP) estimation for 14 sites • Habitat Suitability assessment for 5 sites (in red) • 17 streamflow gauges (daily discharge records over the period 1924-1979 (NFR) Ceola et al. - Hydropower prod. vs. fish habitat suitability: impact and effectiveness of e-flows

Case Study

Potenza and Chienti river basins e-flows scenarios

• 2 alternative e-flow scenarios, Qenv, from Marche administrative district prescriptions 1 – current prescription, PILOT; 2 – soon-to-be-enforced Water Protection Plan prescription, WPP 1) PILOT time-invariant experimental & empirically-based environmental flow release 2) WPP time-variant hydrogeomorphologically-based Qenv, which is function of: - runoff [L/T] Qenv,PILOT < Qenv,WPP(t) - drainage area [L2] Qenv - geographical location [-] - precipitation parameter [-] - elevation parameter [-] - river ecological status [-] Nov-Jan Feb-Mar Apr-Jun Jul-Oct - geomorphology [-] - time-modulation parameter identifying 4 seasons [-] • 2 fish species (Barb & Chub): association of life stages and WPP seasonality

SEASON LIFE STAGE

Jan - Dec

Apr - Jun

Jul - Oct

Adult

Spawn

Young


Computation of Hydropower Production (HPP)

Methods

ROR HP PLANTS computed as in (A) from:

STORAGE HP PLANTS computed as in (B) and (C) from:

1. seasonal FDCs of natural daily inflows and hydropower plant characteristics (min & max exploitable discharge) 2. environmental flows prescriptions (e-flow)

1. time series of natural daily inflows Qin and environmental flows Qenv 2. conceptual routing model and hydropower plant characteristics (min & max exploitable discharge)



Methods

ROR HP PLANTS computed as in (A) from:

STORAGE HP PLANTS computed as in (B) and (C) from:

1. seasonal FDCs of natural daily inflows and hydropower plant characteristics (min & max exploitable discharge) 2. environmental flows prescriptions (e-flow)

1. time series of natural daily inflows Qin and environmental flows Qenv 2. conceptual routing model and hydropower plant characteristics (min & max exploitable discharge)

Prediction of natural flow regime (NFR) at study sites is needed for both computations Ceola et al. - Hydropower prod. vs. fish habitat suitability: impact and effectiveness of e-flows


Methods

Geostatistical prediction of Flow Duration Curves (FDCs) in ungauged sites TNDTK: Total Negative Deviation Top-Kriging Metric of streamflow regime similarity: Total Negative Deviation (TND)

TND embeds key FDC features (slope, low-flows and average values – i.e. hydrologic regime)

Researchgate DOI: 10.13140/RG.2.2.12706.73929 07/2017, At: Port Elizabeth, South Africa, Conference: IAHS Scientific Assembly 2017, Pugliese, A., Castellarin, A., Brath, A., 2014. Geostatistical prediction of flow–duration curves in an index-flow framework. Hydrol Earth Syst Sci 18, 3801–3816. doi:10.5194/hess-18-3801-2014. Skøien, J.O., Merz, R., Blöschl, G., 2006. Top-kriging - geostatistics on stream networks. Hydrol. Earth Syst. Sci. 10, 277–287. doi:10.5194/hess10-277-2006.


Methods


Geostatistical prediction of Flow Duration Curves (FDCs) in ungauged sites TNDTK: Total Negative Deviation Top-Kriging Metric of streamflow regime similarity: Total Negative Deviation (TND)

Prediction of FDC at any ungauged sites x0 Empirical FDCs @ Castelraimondo

Discharge [m3/s]

10 2

TND embeds key FDC features (slope, low-flows and average values – i.e. hydrologic regime)

10 1 10 0

year SEAS1 (Nov-Jan) SEAS 2 (Feb-Mar) SEAS 3 (Apr-Jun) SEAS 4 (Jul-Oct)

10 -1

0

0.2

0.4 0.6 Duration [-]

0.8

1

Pugliese, A., Castellarin, A., Brath, A., 2014. Geostatistical prediction of flow–duration curves in an index-flow framework. Hydrol Earth Syst Sci 18, 3801–3816. doi:10.5194/hess-18-3801-2014. Skøien, J.O., Merz, R., Blöschl, G., 2006. Top-kriging - geostatistics on stream networks. Hydrol. Earth Syst. Sci. 10, 277–287. doi:10.5194/hess10-277-2006.


Methods

Assessment of Habitat Suitability: Weighted Usable Area Index (WUA) index for Barb and Chub fish species

For each site (i.e. 5 plants), 2 alternative habitat suitability criteria (Bicchi et al., 2006 and Rambaldi et al. 1997, valid for Apennine Region in Italy) and 2 alternative methodologies are applied: • PHABSIM: evaluation of composite suitability for each computational cell within a cross section (local values of flow velocity and water depth are PHABSIM for Windows User’s Manual and Exercises (2001) considered) Bovee, K. D., et al., (1998), Stream habitat analysis using the instream flow incremental methodology. USGS/BRD

Cell i

Cross Section Vertical

Young Spawn Adult

Cell Area

vi

Computational Cells

WUA [m2]

di

HScomposite=HSv ·HSd Discharge [m3/s]

From Weighted Usable Area to WUA-index (i.e. Integral of WUA(Duration) over Duration) Ceola et al. - Hydropower prod. vs. fish habitat suitability: impact and effectiveness of e-flows

Methods

Assessment of Habitat Suitability: Weighted Usable Area Index (WUA) index for Barb and Chub fish species

For each site (i.e. 5 plants), 2 alternative habitat suitability criteria (Bicchi et al., 2006 and Rambaldi et al. 1997, valid for Apennine Region in Italy) and 2 alternative methodologies are applied: • HABITAT SUITABILITY DURATION CURVE (HSDC): evaluation of composite suitability for the entire cross section based on average values of water depth and flow velocity (i.e. equivalent rectangular cross section) derived from discharge values by applying Leopold’s scaling equations. HSDC-index (i.e. area below the curve)

00

Castelraimondo Barb Young Chub Young

1 2 Discharge [m3/s]

1

Castelraimondo NFR PILOT WPP

Duration [-]

HScomposite [-]

1

3

0

10-2

100 Discharge [m3/s]

102

1 HScomposite [-]

HScomposite=HSv(Q) ·HSd(Q)

0 0

Castelraimondo – Barb Young NFR PILOT WPP Index @ NFR

Duration [-]

1

WUA-index = HSDC-index · river width Ceola et al. - Hydropower prod. vs. fish habitat suitability: impact and effectiveness of e-flows

Impacts on Hydropower Production (HPP) DHP (%): relative differences in terms of hydropower productivity from PILOT scenario (Qenv,PILOT) to WPP scenario (Qenv,WPP(t)) (positive sign implies loss in productivity)

Season-based average results: All 14 Hydro-power plants grouped Basin Potenza

Chienti

Season YEAR Nov – Jan Feb – Mar Apr – Jun Jul – Oct YEAR Nov – Jan Feb – Mar Apr – Jun Jul – Oct

DHP 13.27% 12.53% 4.29% 8.69% 36.64% 17.38% 17.58% 14.56% 14.79% 30.68%


Results

Impacts on Weighted Usable Area-index (WUA-index)

Results

WUA-index evaluated for each HP site (5 sites), for Barbus Barbus (Barb) WUA-index (mean +/- standard deviation) for the set of 5 study plants: (a) and (d) young-of-the-year (period: Jul.-Oct.); (b) and (e) spawning (period: Apr.- Jun.); (c) and (f) adult (period: entire year). Left and right columns: habitat suitability criteria proposed by Bicchi et al. (2006) and Rambaldi et al. (1997). Filled, striped and dotted patterns represent NFR, PILOT and WPP scenarios, respectively. Ceola et al. - Hydropower prod. vs. fish habitat suitability: impact and effectiveness of e-flows

Impacts on Weighted Usable Area-index (WUA-index)

Results

WUA-index evaluated for each HP site (5 sites), for Leuciscus cephalus (Chub) WUA-index (mean +/- standard deviation) for the set of 5 study plants: (a) and (d) young-of-the-year (period: Jul.-Oct.); (b) and (e) spawning (period: Apr.- Jun.); (c) and (f) adult (period: entire year). Left and right columns: habitat suitability criteria proposed by Bicchi et al. (2006) and Rambaldi et al. (1997). Filled, striped and dotted patterns represent NFR, PILOT and WPP scenarios, respectively. Ceola et al. - Hydropower prod. vs. fish habitat suitability: impact and effectiveness of e-flows

Conclusions From the quantitative estimation of the effects of alternative e-flow prescriptions on hydropower production and habitat suitability of fish species we find: •

Moving from PILOT to WPP is likely to result in a significant decrease in hydropower production, while the ecological effect for Barb and Chub cannot be clearly outlined (i.e. no evident and generalizable WUA-index variation): 1. Hydropower Production: the season Jul-Oct reveals that all hydropower sites present the highest losses (from 15% to 80%) associated to both a limited water resources availability and a relatively high water demand for ecological purposes (i.e. Qenv,WPP > Qenv,PILOT) 2. Habitat Suitability: Different Habitat Suitability Criteria (i.e. 2 are applied in this study) results in different values of WUA-index multiple Habitat Suitability Criteria should be considered

•

The variability associated to different Habitat Suitability Criteria is comparable with the variability between PHABSIM and Habitat Suitability Duration Curve: PHABSIM PROS: local info (i.e. computational cells); consolidated method CONS: detailed cross section hydraulic properties, not always available

HABITAT SUITABILITY DURATION CURVE PROS: easy and fast approach; few hydraulic data (average values) CONS: local scale analysis cannot be performed


Perspectives The proposed analysis, which can be easily adapted to different riparian habitats and hydrological contexts, is a useful tool to guide the derivation of optimal water resource management strategies in order to ensure both hydropower production and fluvial ecosystem protection. Acknowledgments

Serena Ceola University of Bologna

Alessio Pugliese University of Bologna

Giorgio Galeati Water Res. Eng.
