A modified IHACRES rainfall-runoff model for predicting ...Nov 30, 2018 · followed by a linear...

A modified IHACRES rainfall-runoff model for predicting hydrologic response of a river basin system with a relevant groundwater componentIolanda Borzì 1,*, Brunella Bonaccorso 1 and Aldo Fiori 21Department of Engineering, University of Messina, Messina, Italy

2Department of Engineering, Roma Tre University, Rome, Italy

*Correspondence: [email protected]

3rd International Electronic Conference on Water Sciences (ECWS-3)15 – 30 November 2018

A modified IHACRES rainfall-runoff model for predicting hydrologic response of a river basin system with a relevant groundwater componentIolanda Borzì 1,*, Brunella Bonaccorso 1 and Aldo Fiori 2

*[email protected]

On the contrary, instead, rainfall-runoff models often fail to simulate thehydrologic connection between streamsand groundwater system where it tendsto be variable in time and space, as forthe spatial intermittent streams.

This is the case of the Alcantara riverbasin in Sicily region (Italy), whoseupstream is intermittent, while its middlevalley is characterized by perennialsurface flows enriched by spring waterarising from the big aquifer of theNorthern sector of the Etna Volcano.

Introduction

A flow regime can be broadly categorized as perennial, intermittent, or ephemeral. In perennial systems, there is apermanent connection between the stream and groundwater, and good results can be obtained from rainfall-runoffmodels that do not explicitly represent the groundwater store.

Etna Volcano, Sicily, Italy


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Case StudyThe Alcantara river catchment is located in North Eastern Sicily, encompassing the north side of Etna Mountain, the highest

active volcano in Europe. The mountain area on the right side of the river is characterized by volcanic rocks with a very highinfiltration capacity. Here, precipitation and snow melting supply a large aquifer whose groundwater springs at themid/downstream of the river, mixing with surface water coming from the left side of the basin, whose contribution follows therainfall annual variability typical of Mediterranean climate.

Alcantara River Basin andMojo Alcantara Sub-Basin

Alcantara Basin

Mojo Alcantara

Sub-Basin

Area (km2) 603 342

Mean elevation (m) 531 1142

Max elevation (m) 3274 3274

Min elevation (m) 0 510

Groundwater resources are mainly used to supply all themunicipalities located within the river catchment throughlocal aqueducts, as well as the small towns along the Ioniancoast; in addition: the Alcantara river also supplies someindustries, farms and two hydroelectric power plants. Thisarea is also a beautiful environmental reserve.

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Main Informations Table


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• Development and implementation of a model

able to simulate the response of the system

with its groundwater component explicitly

modelled as well as interactions between

aquifer and streamflow.

• Building up of a useful instrument for

enhancement of water resources management

in a complex groundwater fed catchment, the

Alcantara river basin in Sicily, under different

climatic and water demand scenarios.

Objectives of the Study

“Gole dell’Alcantara” – Alcantara Fluvial Park, Sicily, Italy


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Non – Linear Module

Linear Module

Effective Rainfall

Streamflow

Rainfall andTemperature

The IHACRES Model

In the original version of IHACRES, firstly described by Jakeman et al. (1990), therainfall-runoff processes are represented by two modules: a non-linear loss module thattransforms precipitation to effective rainfall considering the influence of the temperature,followed by a linear module based on the classical convolution between effective rainfalland the unit hydrograph to derive the streamflow.

Main advantages and capabilities of the model:

• It is simple, parametrically efficient and statistically rigorous• Inputs data requirements are simple too, requiring only precipitation, temperature and

streamflow• The model provides a unique identification of system response even with only a few

years of input data• The model efficiently describes the dynamic response characteristics of catchments• The model allows to obtain time series of interflow runoff with over-day storage, runoff

from seasonal aquifers and catchment wetness index• The model can be run on any size of catchment• Simulation are quick and computational demand is low

Generic Structure of IHACRES model(excerpted from Jakeman, 1990)


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l

r(t)/c

T(t)r(t)

TemperatureRainfall

s(t)s(t-1)

u(t)

Streamflow Discharge

x0 u(t) x1 u(t)

QUICK SLOW

𝜆1Tank 1Soil

GW

𝜆2

q0(t)q1(t)

y1 q1(t) y2 q1(t)

qr(t)qs(t)

Tank 2Groundwater

Effective Rainfall

Springs Discharge

INPUTS

OU

TPU

TSN

ON

-LIN

EAR

MO

DU

LE

NO

N-L

INEA

R M

OD

ULE

LIN

EAR

MO

DU

LE

For

Effe

ctiv

eR

ain

fall

est

imat

ion

For

Dis

char

gean

d G

rou

nd

wat

er

Re

sou

rce

esti

mat

ion

Structure of the modified IHACRES model

The Modified IHACRES ModelHereafter a modified version of the above synthetically described IHACRESmodel is presented, able to better simulate the groundwater component ofan aquifer system.

The structure of the modified IHACRES model includes three modules:(1) a non linear loss module that transforms precipitation to effectiverainfall by considering the influence of temperature, after this (2) a linearmodule based on the classical convolution between effective rainfall andthe unit hydrograph able to simulate the quick component of the runoff and(3) another non linear module that simulates the slow component of therunoff and that feeds the groundwater storage. From the sum of the quickand the slow components (except for groundwater losses that representsthe aquifer recharge) the total streamflow is derived.

The need of this further non-linear module (3) arises from the necessity toproperly describe the groundwater component of the aquifer system andto model and quantify spring discharges.


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l

r(t)/c

T(t)r(t)

TemperatureRainfall

s(t)s(t-1)

u(t)

Streamflow Discharge

x0 u(t) x1 u(t)

QUICK SLOW

𝜆1Tank 1Soil

GW

𝜆2

q0(t)q1(t)

y1 q1(t) y2 q1(t)

qr(t)qs(t)

Tank 2Groundwater

Effective Rainfall

Springs Discharge

INPUTS

OU

TPU

TSN

ON

-LIN

EAR

MO

DU

LE

NO

N-L

INEA

R M

OD

ULE

LIN

EAR

MO

DU

LE

For

Effe

ctiv

eR

ain

fall

est

imat

ion

For

Dis

char

gean

d G

rou

nd

wat

er

Re

sou

rce

esti

mat

ion

Structure of the Model and Equations

𝒖 𝒕 =𝟏

𝟐ሻ𝒔 𝒕 + 𝒔(𝒕 − 𝟏 − 𝒍

𝒑

∙ 𝒓 𝒕 If1

2ሻ𝑠 𝑡 + 𝑠(𝑡 − 1 > 𝑙

𝜏𝑤 𝑇 𝑡 = 𝜏0 ∙ 𝑒20−𝑇 𝑡 ∙𝑓

Where:𝑠 𝑡 =

ሻ𝑟(𝑡

𝑐+ 1 −

1

𝜏𝑤 𝑇 𝑡∙ 𝑠(𝑡 − 1ሻ

𝒒𝟎(𝒕ሻ =𝒙𝟎𝒕 ∙ ∆𝒕

∙ 𝒖 𝒕 ∙ 𝑨 ∙ ∆𝒕

𝒒𝟏(𝒕ሻ =𝒙𝟏 𝟏 − 𝒆

−𝒕 ∆𝒕𝝀𝟏

𝒕 ∙ ∆𝒕∙ 𝒖 𝒕 ∙ 𝑨 ∙ ∆𝒕

Where:

𝑥0 + 𝑥1 = 1

𝒒𝒔(𝒕ሻ = 𝒒𝟎(𝒕ሻ + 𝒒𝟏𝒚𝟏(𝒕ሻ 𝒒𝒓(𝒕ሻ =𝒚𝟐𝒒𝟏 (𝒕ሻ 𝟏 − 𝒆

−𝒕 ∆𝒕𝝀𝟐

𝒕 ∙ ∆𝒕∙ 𝑨 ∙ ∆𝒕

𝑦1 + 𝑦2 = 1

𝒖 𝒕 = 𝟎 otherwise


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Calibration of the Model

Calibration of the Model (calibration period: 1984-1986)

The model has been calibrated ona 4-year daily streamflow dischargetime series (1984-1986) at MojoAlcantara hydrometric station.

For this case study, there are nospring discharge time seriesavailable, so to work around thisissue, an “A Priori” condition hasbeen used into the calibrationprocess.

Model Calibration has beencarried out in R-Studio Softwareusing the packages “DEoptim” and“hydroGOF”.


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Validation of the Model

Calibration of the Model (calibration period: 1984-1986)

For the validation of the model, the daily streamflowdischarge time series observed at Mojo Alcantarahydrometric station during the period 1987-1988 areused.

Moriasi et al. 2007 and Rittler et al. 2013 suggests that theefficiency of an hydrological model can be considered verysatisfying when the Nash-Sutcliffe Efficiency value invalidation is between 0,5 and 0,65.

MSE (Calibration) NSE (Calibration) MSE (Validation) NSE (Validation)

0,6789 0,5169432 8,780084 0,483667

Performance indicators of the calibration and validation of the model (Mean Square Error and Nash-Sutchliffe Efficency)


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Conclusions and Future Perspectives

The novelty of this modified IHACRES model lies in the fact that the groundwater component and its interaction with thesurface water through spring discharges are modeled through a non-linear module whose equations involves thecalibration of four parameters of easy interpretation.

Results show that the developed model is able to properly reproduce the seasonality in the hydrological response of theaquifer system in combination with the main streamflow.

In particular, the results of model validation can be considered satisfiying, with a Nash-Sutcliffe Efficiency value close to theoptimal range suggested in literature by Moriasi et al. 2007 and Ritter et al 2013

Further researches will address uncertainty and sensitivity analysis of the model and its parameters. More specifically, afirst order sensitivity anaylisis to better understand the influence of parameters on the performance of the model will becarried out, together with an uncertainty analysis based on the PLUE (Profiled Likelihood Uncertainty Estimation) approach.

ReferencesJakeman A.J., Littlewood I.G., Whitehead P.G.; Computation of the instantaneous unit hydrograph and identifiable component flows with application to two small upland catchments, Journal of Hydrology, 117, pp. 275-300, 1990Moriasi, D. N., Arnold, J. G., Van Liew, M. W., Bingner, R. L., Harmel, R. D., & Veith, T. L. Model evaluation guidelines for systematic quantification of accuracy in watershed simulations. Transactions of the ASABE, 50(3), 885-900. 2007Ritter, A.; Muñoz-Carpena, R.; Performance evaluation of hydrological models: statistical significance for reducing subjectivity in goodness-of-fit assessments". Journal of Hydrology. 2013

A modified IHACRES rainfall-runoff model for predicting hydrologic response of a river basin system with a relevant groundwater componentIolanda Borzì 1,*, Brunella Bonaccorso 1 and Aldo Fiori 21Department of Engineering, University of Messina, Messina, Italy

2Department of Engineering, Roma Tre University, Rome, Italy

*Correspondence: [email protected]

3rd International Electronic Conference on Water Sciences (ECWS-3)15 – 30 November 2018

A modified IHACRES rainfall-runoff model for predicting ...Nov 30, 2018 · followed by a linear...

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