long-term monitoring network design with an …dirk kassenaar earthfx inc. watertech 2017 long term...

Long-Term Monitoring Network Design with an Integrated Model

Dirk KassenaarEarthfx Inc.

Watertech 2017

Long Term Monitoring Network Design with an Integrated Model

Long Term Cumulative Effects Monitoring

Long term environmental monitoring is critical, but expensive ▪ Need to maximize the value of each data measurement

▪ Monitoring is a long term commitment

When to start monitoring?▪ The best time to begin monitoring is 20 years ago, the second best time is now

Major questions:▪ What to monitor?

▪ Where to monitor?

▪ How to monitor watershed function?

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Where to monitor: Typical Strategies

Where to monitor? Typical strategies include:

▪ Where complaints occur

▪ Where site access is easy/convenient/cheap

▪ Where there is lots of activity or, much more rarely, “background” conditions

▪ Where there are “data gaps”

• i.e. holes in the “points on the map”

• Either by eye, or through geostatistical standard error analysis

None of these are based on understanding watershed function or response

▪ Data gap analysis is rarely in 3D, and a uniform distribution is not necessarily best

▪ Networks tend to grow and then get “rationalized”, leading to temporal gaps

▪ Rarely are monitoring programs coordinated between SW and GW function

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What to monitor: Flows, levels and function

What to monitor: Need a balance of flows and levels

▪ For a unique solution, you must have one flow (flux) for every water level (potential)

▪ Unfortunate (and common) technical bias

• Groundwater scientists tend to focus on monitoring groundwater levels

• Similarly, surface water scientists tend to focus on flows (streamflow and precipitation)

What to monitor: Need to understand watershed function and response

▪ Primary goal: Monitor effects of water diversions (SW or GW) on water availability

• Human need generally comes first (also conflict and well interference)

▪ Secondary goal: Monitor effects relative to in-stream flow needs (IFN), e-flows, etc.

• Unfortunately, IFN is very difficult to quantify and very complex

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Modelling then Monitoring

What to do first? Modelling or Monitoring? ▪ IAHS “Predictions in Ungauged Basins” (PUB) Decade (2003-2012)▪ …set out to shift the scientific culture of hydrology towards improved scientific understanding of hydrological processes, as

well as associated uncertainties and the development of models with increasing realism and predictive power.

▪ Current problems will be solved by improving models now

Best approach: Integrated Modelling, and then, Integrated Monitoring

▪ Lather, rinse, repeat on a 10 year horizon

Integrated modelling provides the insight needed to design an effective and efficient monitoring program that addresses watershed function and response▪ “A society grows great when old men plant trees whose shade they know they shall never sit in.”

The also applies to monitoring networks

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Case Study: Modelling >> Monitoring

In 2014, Earthfx Inc. was hired by the Cumulative Environmental Management Association (CEMA) to answer the following question:

▪ Is there enough water in the Mackay watershed to sustain a responsible level of development

Cumulative effects analysis requires the integrated assessment of:

▪ Multiple anthropogenic stresses:

• Numerous spatially distributed SW and GW diversions

• Land use change (land clearing, drill pads, roads, etc.)

▪ Intersecting effects on surface and groundwater systems:

• Changes in groundwater levels (drawdowns) in all aquifer systems

• Changes to frequency, duration and severity of low flow conditions

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Introduction

In-situ Steam Assisted Gravity Drainage (SAGD) oil sand operations require a source of fresh water for steam injection.

Groundwater supply wells, generally drawing from aquifers above the oil production zone, are a preferred source.

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From MEG Energy Corp.


Study Area

MacKay River Watershed is located immediately north-west of Fort McMurrray, AB▪ Includes Syncrude Mine site and

numerous SAGD operations

Watershed Area: 5,600 km2

Model Area: 7,900 km2

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LegendLake

NamurLake


Approach

Step 1: Integrated Model Development and Calibration▪ Model Development: Compile Geology, Hydrogeology, Climate, Hydrology, Hydraulics

▪ Integrated model calibration: Full reconciliation of entire hydrologic cycle (water budget)

Step 2: Sustainability Assessment▪ Define Assessment Criteria and Climate Period

• Define aquifer drawdown and streamflow impact sustainability thresholds

• Select a representative “surrogate” climate assessment period (25 years)

▪ Simulate Pre-development (Baseline), Current and Full Build conditions over the climate period

Step 3: Assess how to monitor the upcoming changes

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Integrated Modelling Approach: Advantages

Study Approach: Fully integrated surface water and groundwater model

Better representation of:▪ Groundwater recharge and

Dunnian GW feedback

▪ Streamflow and induced leakage

▪ SW/GW storage

▪ Cumulative effects of all SW and GW diversions

Flux inputs and calibration targets▪ Measured precipitation as input

▪ Calibration to total streamflow and measured GW levels

▪ Integrated use of all monitoring data

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Selected Model: USGS GSFLOW

USGS integrated GW/SW model▪ Based on MODFLOW-NWT and PRMS (Precipitation-Runoff Modelling System)

▪ Open-source, proven and very well documented

▪ Fully-distributed: Cell-based representation

▪ Excellent balance of hydrology, hydraulics and GW

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Study Area Features

Topography (600 m of relief)▪ Birch Mountains

▪ Thickwood Hills

Incised river and stream network▪ MacKay River – main channel

▪ Dover and Dunkirk Tributaries

▪ Athabasca River: South and eastern boundary

Legend and Namur Lakes▪ Plus over 100 other lakes in study area

Extensive muskeg and wetlands

Bedrock Channel Aquifers ▪ Key GW supply source for multiple projects

Anthropogenic Stresses▪ Syncrude Mine

▪ SW and GW Diversions

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AMBI, 2013)


GSFLOW: Multi-Resolution

GSFLOW is unique in that the resolution of the model can be adjusted to match key features

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Climate inputs( 2.5 km cells)

Surface Hydrology/Soil Zone( 200x200 m cells)

Sub-surface Hydrogeologic Layers( 13 layers of 400x400 m cells)

Stream NetworkLinear 1-D Channel segments(4000 km of streams represented, independent of grid resolution)


Model Grid

Fully distributed model: Every cell has unique properties

GW grid: 400 m by 400 m cells▪ Selected to match assessment

averaging criteria (impact at 150 m from a well) but avoid focus on specific water users.

▪ Can be refined for future studies

SW Grid: 200x200 m cells▪ Improved representation of overland

flow, wetlands, interflow and soil zone processes and properties

Stream routing:▪ All streams and rivers simulated

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400x400 m GW grid


Stratigraphic Model: 19 layers

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After AGS Source: Andriashek and Atkinson, 2007

Empress Channel Sands:Key water supply aquifer

Viking Aquifer

Aquifer


GW Level Data

803 wells with water level data

Very limited long term temporal monitoring data (GOWN)

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Climate Inputs

Precipitation and temperature interpolated on a daily basis over a 2.5km x 2.5km grid▪ Inverse distance squared weighting

25 year daily climate time series input for each grid cell

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Vegetative Cover Classes

26 wetland and vegetative cover classes▪ 17 types of wetlands

Model parameters assigned by class:▪ Seasonal Cover density

▪ Vegetation indices

▪ Soil zone properties

▪ Overland flow and shallow interflow parameters

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Overland Flow

Overland flow and interflow simulated with a topographically defined cascade network

200x200m cell representation

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Model Calibration and Validation

Calibrated then verified against over 38 year period

A range of hydroclimatic conditions simulated

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Validation Calibration and assessment


Model Calibration and Validation

Hydrologic submodel and the final integrated model were calibrated against streamflow observations at 6 Water Survey (EC) and RAMP stations

Historical observations at discontinued stream gauges were an important source of insight

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Model Calibration and Validation Good match to streamflow

observations at study area gauges

Daily Nash-Sutcliffe 0.65

Monthly Nash-Sutcliffe 0.75

Good match to validation period: Model has adequate predictive power

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Distributed Results

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Distributed Results (GSFLOW)

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GW/SW Animation

Animation shows spring melt and changes in GW levels and streamflow

25- Summary of Model Development


Diversion Scenarios

Baseline: No pumping

Current Conditions:▪ 4 Operations including 11

pumped wells.

Full-Build Conditions:▪ 14 Operations including 42

pumped wells.

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CurrentOperations

CurrentOperations

CurrentOperations


Land Use Change

Processing facilities and well pads▪ Assumed to be 100m by 100m gravel

pads spaced 500m on center

▪ Reduced ET, due to the loss of vegetation, increased runoff

Full Build Scenario: ▪ Drill pads are estimated to cover 6% of

the planned project areas;

▪ Roads, pipelines, and facilities cover another 4%.

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GSFLOW Outputs

Spring change in water levels and streamflow

28- Summary of Model Development

Review of Cumulative Impacts – MacKay River Watershed

Review of Cumulative Impacts – MacKay River Watershed

INSIGHTS FOR MONITORING NETWORK DESIGN

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Functional Insights >Monitoring Network Design

We can now use the calibrated integrated model to design an optimum monitoring and management plan

How does the SW and GW system function?▪ Natural response to seasonal and inter-annual climate processes

How does the watershed respond to current and future stresses?▪ Response to proposed changes in SW and GW diversions beyond natural variation

With functional knowledge, how and where should we monitor?

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GSFLOW GW/SW Water Budgets

Significant inter-annual and seasonal storage due to snowpack, frozen ground and climate variability

Water budget analysis indicates that system includes a degree of “self-buffering”

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-4

-3

-2

-1

0

1

2

3

4

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Avg

Flo

ws

(mm

/mo

nth

)

Monthly Average GW Inflows and Outflows - Pre-Development Conditions

Lake Seepage Stream Leakage Surf Leakage Recharge Wells Net Const. Head Net Storage

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-15

-10

-5

0

5

10

15

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1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

Flo

ws

(mm

/yr)

Simulated Inflows and Outflows by Water Year - Pre-Development Conditions

Lake Seepage Stream Leakage Surface Leakage Recharge Wells Net Const. Head Net Storage


Seasonal WL Change

Model identifies locations with significant shallow aquifer change in water levels (and streamflow) in response to spring melt

Identifies sensitive streams and wetlands

Locations with significant shallow spring water level rise would likely be sensitive to both changes in land use and shallow aquifer water diversions

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Change in headwater spring flows

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April May


Monitoring Natural Watershed Function

Model provides insight into the natural seasonal and inter-annual variability

Model identifies “sensitive” stream reaches and shallow aquifers

A stream gauge located in the upper middle of the watershed would collectively monitor changes in shallow groundwater levels

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May


Deep Aquifer Drawdowns

Deep aquifer drawdowns vary significantly depending on degree of aquifer confinement and recharge

Local site monitoring will be suitable for some locations

A few deep regional wells will be needed to monitor distributed drawdown in Birch Mountain area

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Grand Rapids Aquifer

Layer 8 Drawdowns


Shallow Aquifer Drawdowns

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Overburden Aquifers

Layer 1 Drawdowns

Shallow aquifer drawdowns depend on local aquifer geometry and recharge

Local site groundwater monitoring, together with cumulative monitoring of headwater impacts via stream gauges, is likely optimal


Integrated Impact

Overlay of GW drawdowns and changes in stream flow indicate that impacts will be felt across the entire watershed due to the 3D nature of the GW diversions

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390.0

395.0

400.0

405.0

410.0

415.0

420.0

425.0

430.0

435.0

440.0

445.0

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

Gro

un

dw

ateE

leva

tio

n (m

asl)

Surrogate Climate Years

Pre-Development Current Conditions Full Build with Land UseLocation 5 - Empress Channel

Integrated Assessment

Model provides integrated insight into the magnitude of seasonal, inter-annual and diversion effects

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510.0

510.5

511.0

511.5

512.0

512.5

513.0

513.5

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514.5

515.0

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

Gro

un

dw

ateE

lev

atio

n (

mas

l)


Pre-Development Current Conditions Full Build with Land UseLocation 1 - Viking

491.2

491.4

491.6

491.8

492.0

492.2

492.4

492.6

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

Gro

un

dw

ateE

leva

tio

n (

mas

l)


Pre-Development Current Conditions Full Build with Land UseLocation 3 - Viking


SW Sustainability Assessment

IFN analysis, using the Alberta Desktop Method, can be completed at any stream location in the watershed

ADM Threshold for Mackay River at Fort McKay▪ ADM Criteria 1 - fails for select days, as shown in red

▪ ADM Criteria 2 - never more than 15% diverted

Numerous other stream locations also assessed

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Functional Insights >Monitoring Network Design

With an understanding the natural seasonal variation in the system we can truly evaluate response to future diversions and land use change

Unlike agricultural water use, SAGD water use relatively uniform on a seasonal basis. ▪ Uniform diversions can result in significant effects during key seasonal flow periods

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Water Budget Comparisons

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-20

-15

-10

-5

0

5

10

15

20

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

Flo

ws

(mm

/yr)

Simulated Inflows and Outflows by Water Year - Pre-Development Conditions


-20

-15

-10

-5

0

5

10

15

20

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

Flo

ws

(mm

/yr)

Simulated Inflows and Outflows by Water Year - Full Build Conditions


Pre-development shows how wet and dry years replenish and deplete storage (royal blue)

Full build scenario shows greater fluctuations in storage


Water Budget Comparisons Winter pumping depletes storage, replenished by April recharge.

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Full-Build ConditionsBaseline Conditions


Temporal Effects of Winter Pumping

Winter pumping under frozen ground conditions depletes shallow aquifer storage

Baseflow discharge in May is reduced by 50% due to freshet replenishment of shallow aquifer storage

Effect is significant, but very difficult to monitor in stream flow because the baseflow change is masked by high spring runoff

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0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Avera

ge M

on

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ate

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isc

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o

Str

ea

ms (

mm

/ye

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Pre-Development

Full Build

Average Monthly GW Discharge to Streams


Conclusions

An integrated model is optimal for a monitoring network design:

▪ The model development process provides a structured and integrated data assessment framework

▪ Model provides true insight into natural watershed function and stress response

• Modelling provides a process-driven data gap analysis

▪ Model provides expected magnitude of both local and distributed impacts

▪ Model cost is significantly less than an inefficient long term monitoring network

Fully integrated models:

▪ Better use and integration of flux and potential measurements

• Balanced use of flux (SW flows and precip) and levels (GW levels, wetland and lake stage

▪ No need to partition runoff and baseflow during calibration

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Conclusions

Monitoring Strategies

▪ For a unique solution, you must have one flow (flux) for every water level (potential)

▪ Avoid the common technical bias

• Groundwater scientists install stream flow gauges to monitor shallow cumulative impacts

• Similarly, surface water scientists monitor lake and wetlands levels (and shallow piezometers) to headwater discharge

Overall, and integrated modelling and integrated monitoring approach is optimal

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