The hydrogeological conceptual site model for the managed...

Lisboa, 09/10/14

The hydrogeological conceptual site model for the managed aquifer recharge in the WARBO project

Summer School WARBO 2014

Tiago Carvalho


Hydrogeological Conceptual Site Models

Scenarios of the behavior of the aquifers (or hydrogeological systems), intended to explain its behavior and its interactions with the other «branches» of the water cycle and the ecosystems

(e.g Beven, 2001, Fetter 2001, Fitts 2012)

Description and inventorying of the various natural and anthropogenic factors that govern and contribute to the groundwater movement . It may answer the following questions: (Kresic & Mikszewski, 2012)

– Where are is the recharge area?

– Where are the discharge areas?

– What kind of media does it flow? What are its main characteristics?

– How much water is there, and how fast does it flows?

– How did the groundwater system behave in the past, and how will it change in the future, based on natural and anthropogenic influences?

Lisboa, 09/10/14 Tiago Carvalho 2


Hydrogeological Conceptual Site Models

The Hydrogeological Conceptual Site Models is not a goal, per se. It‘s a instrument for the management, development and monitoring of projects that involve aquifers and groundwater.

The hydrogeological conceptual model is dynamic and changes in time, according to the available technical and scientific knowledge.

For projects of:

- Water Supply

- Water Management

- Managed Aquifer Recharge

- Contamination Control

- Aquifer and ecosystem decontamination and yield

- Springs and water well protection

- Evaluation of environmental impacts



Hydrogeological Conceptual Site Models: Basic information

Geology and Hydrogeology – Regional Geological and

Hydrogeological context – Aquifer type; Thickness; – Faults, Overthrust

– Stratigraphy column – Logs analysis – Geophysics

– Hydrogeological inventory – Groundwater point location,

and water characteristics – Hydrogeological characteristics:

– Hydraulic permeability; – Transmissivity – Storage coefficient

– Piezometric Level; Hydraulic Gradient


Source: Kresic & Mikszewski (2012)



Geomorphology (Topography):

– Groundwater flow direction is very often correlated with the topography.

– Possible to define the contribution areas, with a delimitation of the catchments

– Exceptions:

– Heat sources

– Gas sources

– Faults

– Overthrusts


Source:Kresic & Mikszewski (2012)



Climate

– Necessary for the hydrological balance of the system;

– Main parameters:

• Precipitation

• Temperature

• Evapotranspiration

( Turc, Penman–Monteith)

• Evaporation

(Penman)

– Verify the time delay between the maximum precipitation and the highest water level


Source: Kresic & Mikszewski (2012)


Sourve: Kresic & Mikszewski (2012)


Hydrology

– Surface and Groundwater are part of the same hydrological cycle and therefore are closely connected, specially in freatic acquifers.

– Understanding discharge and recharge areas

– Base flow calculation


Castany & Berkalof metod (1970): Calculation of the Base flow (average during no precipitation events

1) Infiltration = (P-E)* Qbaseflow/Qtotal 2) Infiltration = Qbaseflow/Area



Land use and Land Cover

– Impacts in quantity and quality of the groundwater highly dependent on the activities at the surface, specially in the recharge area.

– Tendencies:

• Replacement of forest areas for agriculture purposes;

• City growth – soil impermeabilization (Poor countries)

• USA – Decentralization of the cities, and recovery of agricultural areas for deforestation



WARBO Project (2012 -2014)

WARBO - WAter Re-BOrn

Managed Aquifer Recharge: Technology for the sustainable management of the water resources. Financed in 2011 from the European Commission http://www.warbo-life.eu/

Objectives:

• Construction/ use of structures for managed aquifer recharge

• Estimation of the necessary water volume and operational time for the recuperation of the piezometric levels in the aquifer and/or for the water quality improvement

• Evaluation of the efficiency of the artificial recharge

• Development of the scientific knowledge over the use of several subjects of investigation in the study and management of MAR

• Development of models for water management


http://www.warbo-life.eu/




Managed Aquifer Recharge

Artificial recharge is the process of introducing surface water in the groundwater system, through surface dispersion, recharge wells, or by changing the natural conditions to increase infiltration.


Objectives:

• Seasonal storage

• Long term storage

• Emergency storage

• Disinfection by-product reduction

• Restore groundwater levels

• Reduce subsidence

• Support in the distribution systems

• Improve water quality

• Prevent saltwater intrusion

• Reduce environmental effects of streamflow variation

• Nutrient reduction in agricultural runoff

• Enhance wellfield production

• Delay expantion of water facilities

• Reclaimed storage water for re use

• Soil aquifer treatment

• Stabilize agressive water

• Hydraulic control of contaminant plumes

• Temperature control

Addapted from David, R, Pyne, G (2005)


WARBO project: Test Sites



Fruili-Venezia-Giulia


Source: University Udine


Fruili-Venezia-Giulia (FVG) regional hydrogeological conceptual model


Source: ARPA FVG (2011)


Test site 1: Mereto di Tomba



Test site 1: Mereto di Tomba - Hydrogeology


0

1000

2000

3000

4000

5000 35

65

1975 1978 1981 1984 1987 1990 1993 1996 1999 2002 2005 2008

An

ual

Pre

cip

itat

ion

(mm

)

NH

E (m

)

Precipitation 0151 0155 0156


Test site 1: Mereto di Tomba - Hydrogeology


Ks = 2,3 . 10-4 m/s = 19 m/d


Test site 1: Mereto di Tomba – Calculating Infiltration


Q = Flow A =Area K = Hydraulic permeability Dpond = Water hight L = Distance to the water front Hwf = Capilarity Infiltration rate = Q/A = 60,8 cm/h

Green-Ampt Equation


Ferrara, 05/09/13 Tiago Carvalho 20

Source: OGS, 2013


Test site 1: Mereto di Tomba – Pumping Test

Two equiped wells

– Tubo 1: Pump with a fow of 2,87 l/s

– Tubo 2:located 12 meters away from tubo 1

Logan’s Aproach:

– T = 1,12 * Qs


Tubo 1 Tubo 2

Flow(l/s) 2,87 --

NHE (m) 49,15 49,15

NHD (m) 49,53 49,15

S (m) 0,38 0

Qs (m³/s/m) 653 --

T (m²/s) 8,5 * 10-3

K (m/s) 4,2 * 10-4

Duration(min) 90


Test site 1: Mereto di Tomba – Modello concetualle


Test site 1: Mereto di Tomba – 1st Conceptual model Influence area Todd formula: 118 ha Jacob-Bears formula: 6 ha (for 180 days)


Test site 1: Mereto di Tomba – Recharge findings – Model calibration

• Construction of shallow wells demonstrated the presence of a perched aquifer.

• Hydraulic impossibility to transfer 118 l/s from the channel to the pond;

• Two recharge experiments:

– 40 days: December 13 and January 14 ( average flow of 7 l/s)

– 224 days: March till October 14 (average flow of 13 l/s)

• Level stabilization at around 1,5 meters with a flow of 13 l/s

• Reversed calculation with the Green-Ampt equation changed the hydraulic conductivity to a lower magnitude order (for all the non saturated zone)

• With the new calculated hydraulic conductivity the maximum flow would be 26,4 l/s

• Level in the piezometers are stable, with few signs of influence

• Tracer tests proved the recharge efficiency

• Relevant geochemical evidences of recharge efficiency



Flow vs Water level in the pond


0

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100

150

200

250

0

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20/Mar 27/Mar 3/Abr 10/Abr 17/Abr 24/Abr 1/Mai 8/Mai 15/Mai 22/Mai 29/Mai 5/Jun 12/Jun

Wat

er

Lve

l (cm

)

Flo

w (

m3

/h)

Flow Level


Test site 1: Mereto di Tomba – Recharge Influence





Recharge 7 l/s

Recharge 13 l/s

Recharge 13 l/s




0

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Dez/13 Dez/13 Jan/14 Mar/14 Abr/14 Mai/14 Jun/14 Jul/14 Ago/14 Set/14

NO

3 (

mg/

l)

Ledra A1 PZ11 PZ12 PZ6

Recharge 7 l/s

Recharge 13 l/s

Recharge 13 l/s


Tracer tests


0

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21/5/14 22/5/14 23/5/14 24/5/14 25/5/14 26/5/14 27/5/14 28/5/14 29/5/14 30/5/14

Ura

nin

(p

pb

)

A1 PZ12 PZ13 PZ6


Test site 1: Mereto di Tomba – Mereto Conclusions

• Low effect on the water levels. Extremely high transmissivity and diffusivity of the water

• Very efficient for the enhancement of the water quality. Effects are seen in a few days.

• Evidences of influence in the water chemistry in PZ12 and PZ6

• Recharge water follows more than one direction for the aquifer recharge as seen in the tracer test.

• If the test site can be developed to test site full potential (25,7 l/s) during long time periods, than the influence radius of the project can be felt up to 800 meters downstream, with a radius of about 100 meters) (Wyssling Formula)



Test site 1: Mereto di Tomba – Hydrogeological Conceptual Model



Test site 2: Zona Industriale de Ponte Rosso

• Low Plains –multistrata aquifer

• Water withdraws from the lower confined and artesian aquifers

• Water works for treatment of all consortium effluents

• Phytodepuration system with 3 lagoons.

• Available water resources: 30 m3/h, mostly constant all year round

Objective:

Definition of a methodology for the utilization of an industrial effluent for the recharge of the phreatic aquifer



Test site 2: Zona Industriale de Ponte Rosso - Geology

Lithological map


Source: University Udine

Thickness of the phreatic aquifer


Test site 2: Zona Industrial de Ponte Rosso - Geology

Vertical lithostratigraphic section


Source sections: University Udine, 2012


Test site 2: Zona Industriale de Ponte Rosso – Hydrogeological caracteristics

Two wells were instrumented

– Tubo 1: Pump with a flow of 22,6 l/s

– Tubo 2: located 59 meters away

Logan’s Aproach:

– T = 1,12 * Qs


Parametro idrogeologico Tubo 1 Tubo 2

Flow (l/s) 22,57 --

NHE (m) 2,50 2,48

NHD (m) 2,75 2,48

S (m) 0,25 0

Qs (m³/s/m) 7797 --

T (m²/s) 1,0 * 10-1

K (m/s) 1,7 * 10-2

Time (min) 80


Test site 3: Copparo – Geology


Source: Regione Emilia-Romagna, 2009


Test site 3: Copparo

Infiltration pond



Ferrara, 05/09/13 Tiago Carvalho 39


Test site 3: Copparo – Geology



Test site 3: Copparo – 1st conceptual model

First conceptional model


K = 10-5 A = 4*1522 = 6088 m2 I = ΔH/L = 2/(13-2,5) = 0,17 Q = 10, 5 l/s


Test site 3: Copparo – Pond assessment

Infiltration pond




Source: Università Ferrara, 2012


Test site 3: Copparo – New piezometer – estimating hydraulic properties


-5.00

-4.00

-3.00

-2.00

1 10 100 1000

P12

N22

-0.60

-0.50

-0.40

-0.30

-0.20

-0.10

0.00

1 10 100 1000

P11

N21

Analysis with Cooper-Jacob Formula First Confined or semiconfined level: K =4,2 * 10-5 m/s (3,7 m/d)

Second confined aquifer level

K = 1,2 *10-4 m/s (10,7 m/d)


Test site 3: Copparo – Paleochannel downsizing



Test site 3: Copparo – Piezometric level monitoring


0

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-1.6

-1.4

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-1

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-0.6

M/13 A/13 M/13 J/13 J/13 A/13 S/13 O/13 N/13 D/13 J/14

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cip

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(m

m)

Pie

zom

etr

ic le

vel (

m)

Precipitation P10 P12 Pond


Test site 3: Copparo – Estimating the pond-aquifer connection area


Darcy’s law: Q = K * Aconnection with aquifer * i

Evaporazione – Q? Q = P – E (mm) * Apond

K =4,2 * 10-5 m/s (3,7 m/d) i = Δh/D = 0,04 Aconnection with aquifer = ??

Estimated in 2340 m2 (4,9 % of the pond area)


Current conceptional model


Variable Evaporation TºC; sun hours; Wind Speed

Infiltration = 6 l/s

ΔH = 1,1 m

L= 9 -1,6 m

A = 2340 m2

Copparo


Test site 3: Copparo – Recharge prediction


Scenario 1 Scenario 2 Scenario 3 Scenario 4 Scenario 5

Connection at

depths >8

Estimated from

evaporation

Connection at

depths >7

Connection at

depths >6

Full connection

with the

Paleochannel

Area (m2) 17.4 2340 3021.1 9276.8 10437.24

K (m/s)

i

Q (m3/s) 4.46E-05 6.00E-03 7.75E-03 2.38E-02 2.68E-02

Q (l/s) 0.04 6.00 7.75 23.79 26.76

Area Cava (m2)

Evaporazione (mm/d) 0.08 14.01 43.01 48.39

4.20E-05

0.0611

47785


Test site 3: Copparo – Model Calibration

• Recharge activity still under way since May 20 th with 3 l/s. Later the value was increased to 10 l/s

• The activity was interrupted due to expantion works of the pond .

• Calibration to be refined with:

– Gathering of the flow data

– Gathering of the piezometric and chemical data in the pond and in the nearby piezometers

– Comparation with the metereological effects



Test site 3: Copparo – Geophisical recharge evidences



Conclusions

• Hydrogeological conceptual site models have always a greater level of detail than the regional ones. Importance of Downscaling.

• The hydrogeological conceptual model is dynamic and according to the available technical and scientific knowledge. More investigations may call for a adaptation of the current model

• Multidisciplinary (Geology, Hydrogeology, Geophysics, Geochemistry, Numerical Modeling…)

• It’s a decision making tool, for water management, process management or water project deleopment

• Its simplicity makes it «attractive» to a broader audience


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