applications of integrated models to watershed and sub-watershed scale analysis: a canadian context

Applications of Integrated Models to Watershed and Sub-Watershed Scale Analysis: A Canadian Context

E.J. Wexler, P.J. Thompson, J.D.C. Kassenaar, M. Takeda Earthfx Incorporated XXI International Conference Computational Methods in Water Resources, June 2016

Watershed-Scale Integrated Modelling in a Canadian Context

Historical Perspective: Ontario

1990 – 2000 ▪ Groundwater models rarely used for engineering design or

impact assessment. Simple water budgets and aquifer tests

2001-2003 ▪ Steady state groundwater models for Ontario Municipal Groundwater

Studies and some quarry impact studies

▪ After Walkerton disaster, Source Water Protection called for multi-tiered assessment of watersheds and municipal supply

2003 – Present ▪ Loosely-coupled hydrologic/groundwater models for Tier 2 and 3

Key questions at Tier 3 level: ▪ Impact of municipal wells on wetlands and coldwater streams

▪ Impact of drought on municipal wells

▪ Impact of future development on groundwater recharge

▪ We developed 7 integrated models for Tier 3 watershed assessments to answer these questions

2 - History in Ontario/Canada

CMWR 2016

Integrated Watershed Models by

Earthfx


Integrated Models: Canadian Applications

Watershed Management ▪ Water Budgets (Current/Future)

▪ Source Water Protection

▪ Irrigation demand management

▪ Ecological Flow Needs

Land Development ▪ Cumulative impact of development

▪ Low Impact Design alternatives

Resource Extraction ▪ Quarry/Mine impact

▪ In-Situ oil sands development

▪ Mine-site management

Climate Change Adaptation

3 - Model Applications


Integrated Models

Integrated models consider both groundwater and surface water flow.

Feedback between the two systems can dominate in some hydrologic settings

For example, shallow water table influences:

▪ Evapotranspiration rates

▪ Dunnian (saturation excess) runoff

▪ Key for representing groundwater interaction with streams, lakes, and wetlands.

4 - Definitions

U n s a t u r a t e d

z o n e

S t r e a m S t r e a m

G r a v i t y d r a i n a g e

R e c h a r g e

G r o u n d - w a t e r f l o w

Interflow

ET

Dunnian Runoff


USGS GSFLOW Code

Many integrated modelling codes

We use the USGS integrated GSFLOW code for watershed and engineering-scale studies: ▪ Open-source, proven, and very well documented

▪ Combines two USGS models: MODFLOW and PRMS (Precipitation-Runoff Modeling System)

▪ Fully-distributed: cell-based representation of hydrology and groundwater

Good balance of hydrology, hydraulics, and groundwater flow

5 - GSFLOW


GSFLOW: Multi-Resolution

6

Climate inputs (Gridded or by gauge)

Hydrology/Soil Zone (PRMS HRUs)

Hydrogeologic Layers ( MODFLOW finite-difference grid)

Stream Network 1-D Channel segments

- GSFLOW

MODFLOW-NWT



CASE STUDY 1: ORO MORAINE

7 - Case Study 1


Oro Moraine: Geologic Setting

Three subwatersheds discharging to Lake Simcoe

Oro Moraine is a high-recharge feature

Feeds wetlands and headwater streams

Model boundary expanded to encompass all Moraine-fed watersheds

Complex geology – best seen in section

8 - Oro Moraine

Oro Moraine

Model Boundary

Study subwatersheds


Oro Moraine: Geologic Setting

Multiple tills and sand layers

Cut across by “tunnel channels”

9 - Oro Moraine

Oro Moraine

Tunnel Channel occupied by Cold Water Creek

Lake Simcoe


Oro Moraine: Hydrology

GSFLOW model represents all stream segments, lakes, and wetlands

Calibrated to daily and monthly flows at four stream gauges

Validated against historical low flow periods

10 - Oro Moraine

Coldwater Creek (02ED007)


Oro Moraine: Groundwater

Shallow system show influence of topography and streams.

Calibrated against over 3400 static water level measurements

Fewer (10) transient monitors

Transient model matches seasonal patterns

11 - Oro Moraine


Oro Moraine: 10-year Historical Drought

Used daily climate data from 1956-1967 drought to analyze subwatersheds response

Drought sensitivity depended on whether streams were linked to Oro Moraine or recharged locally

12 - Oro Moraine

1953-1967

Low

High – Tribs Low - Main

High


Oro Moraine: Groundwater Pathways

Particle tracks show shallow and deep flow systems

Oro Moraine mainly feeds streams and wetlands on flanks

Geology influences stream/aquifer interactions

Deep flow system feeds distant features

13 - Oro Moraine


Oro Moraine: Climate Change

Sampled a range of GCMs.

Used results to scale baseline T and precip.

Ensemble of climate simulations show: ▪ Earlier spring freshet

▪ Reduction in summer flows due to low summer rainfall and longer recession.

14 - Oro Moraine

Jan Y1 Jan Y2 Jan Y3 Note log scale for flow

Flow versus Time - Oro South


Oro Moraine: Climate Change

Integrated models useful for predictive analysis

Important Factors: ▪ Underlying geology

▪ Connection to regional high recharge features

▪ Storage

Drought-sensitive watersheds tended to be more sensitive to climate change.

Click for Animation

15 - Oro Moraine

Baseline CGCM3T63

https://youtu.be/Er26NVP54YU?t=1m10s



CASE STUDY 2 CUMULATIVE IMPACT OF IN-SITU OIL SAND DEVELOPMENT

16 - Case Study 2

From MEG Energy Corp.


MacKay Watershed: Setting

Watershed features: ▪ 600 m of topographic relief

▪ Incised rivers and streams

▪ Over 100 lakes

▪ Extensive muskeg and wetlands

Numerous oil sands operations ▪ Open Pit and In-situ Steam Assisted Gravity

Drainage (SAGD)

▪ Water takings from both surface water and groundwater (diversions)

▪ Clear cutting, well pads, roads, and processing facilities affect recharge/runoff

Model to assess future impacts of expanded SAGD operations

17 - MacKay Watershed

Ells River

Athabasca River

Ath

abasc

a R

iver


MacKay Watershed: Hydrostratigraphic Model


After AGS Source: Andriashek and Atkinson, 2007

McMurray FM

Oil Sands

Grand Rapids aquifer

Viking aquifer

Empress Channel Sands: Key water supply aquifer


MacKay Watershed: Overland Flow

Overland flow (runoff/runon) and interflow simulated with a topographically-controlled cascade network



MacKay Watershed: Wetland Classes

Most of area covered by muskeg

26 wetland and vegetative cover classes used to parameterize the model

Mapping by Ducks Unlimited. (Even in the middle of nowhere, good datasets can be found!)



MacKay Watershed: Frozen Ground

We noted large lag between freshet and groundwater recharge

Couldn’t match with existing model

Added new frozen ground module for GSFLOW ▪ GSFLOW is Open Source!

Based on modified Stefan Equation ▪ Derived by the U.S. Army Corps of Engineers

Model code follows Emerson (1994)

Freezes from top; thaws from top and bottom


𝑋𝑓 =86,400𝐾𝑓𝐼𝑓

𝐿 + 𝐶 𝑇𝑎 +𝐼𝑓

2𝑡

0.5

𝑋𝑓 = 𝑑𝑒𝑝𝑡ℎ 𝑜𝑓 𝑓𝑟𝑜𝑠𝑡 𝐾𝑓 = 𝑡ℎ𝑒𝑟𝑚𝑎𝑙 𝑐𝑜𝑛𝑑𝑢𝑐𝑡𝑖𝑣𝑖𝑡𝑦

𝐼𝑓 = 𝑓𝑟𝑜𝑠𝑡 𝑖𝑛𝑑𝑒𝑥 𝑑𝑒𝑔𝑟𝑒𝑒 𝑑𝑎𝑦𝑠

𝐿 = 𝑙𝑎𝑡𝑒𝑛𝑡 ℎ𝑒𝑎𝑡 𝐶 = 𝑣𝑜𝑙𝑢𝑚𝑒𝑡𝑟𝑖𝑐 ℎ𝑒𝑎𝑡 𝑐𝑎𝑝𝑐𝑖𝑡𝑦 𝑇𝑎 = 𝑚𝑒𝑎𝑛 𝑎𝑛𝑛𝑢𝑎𝑙 𝑠𝑜𝑖𝑙 𝑡𝑒𝑚𝑝𝑒𝑟𝑎𝑡𝑢𝑟𝑒 𝑡 = 𝑑𝑢𝑟𝑎𝑡𝑖𝑜𝑛 𝑜𝑓 𝑡ℎ𝑒 𝑓𝑟𝑒𝑒𝑧𝑖𝑛𝑔 𝑝𝑒𝑟𝑖𝑜𝑑

𝑤ℎ𝑒𝑟𝑒


MacKay Watershed: Frozen Ground

Frozen soil dynamics affect both surface and subsurface processes: ▪ Observed high runoff during spring freshet; but no winter recharge

▪ Groundwater discharge to streams and wetlands reduced in winter

Good match to observed with new module



MacKay Watershed: Model Calibration


200

300

400

500

600

700

800

200 300 400 500 600 700 800

Sim

ula

ted

(m

asl)

Observed (masl)

Overburden

Empress Fm.

Labiche Aquitard

Viking Aquifer

Joli Fou Aquitard

Grand Rapids Aquifer

Clearwater Aquitard

McMurray Aquifer/Aquitard

Cooking Lake Aquifer

1:1

Error Intervals (±10 m)

Static Water Levels

Daily Streamflow

Daily Nash-Sutcliffe 0.65

Monthly Nash-Sutcliffe 0.75

Multiple steps: first as stand-alone models; then as a coupled model

Major advantage of GSFLOW, submodels can be run separately

Very little transient groundwater data


MacKay Watershed: PRMS Sub-model Results



MacKay Watershed: Future Scenario

Baseline: No pumping

Current Conditions: ▪ 4 Operations including 11 wells.

Full-Build Conditions: ▪ 14 Operations including 42 wells.

▪ Drill pads are estimated to cover 6% of the planned project areas;

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


Current Operations


MacKay Watershed: Groundwater Impacts


Cumulative drawdowns are significant, mainly in deeper highly-confined aquifer units

Drawdowns generally stable after 20 years, suggesting sustainable water use

Localized zones where drawdown exceed 50% of total available

Viking/Pelican Aquifer

Layer 5 Drawdowns


MacKay Watershed: Impacts to Streamflow

Evaluated simulated streamflows with a number of environmental flow criteria

Impacts to simulated streamflow in the major reaches is small

Locally, some stream reaches are severely impacted around large diversions ▪ Shows that groundwater diversions mat

locally induce leakage that exceeds ecological baseflow criteria

Effectively determined by integrated model



Case Study 3 – Wellfield Next to Reservoir

28 - Milton

Large wellfield directly adjacent to a large flood control reservoir

Transient integrated modelling undertaken to analyze the influence of reservoir operations on wellfield sustainability

Identified previously unknown linkages between the wells and the surface water system

Simulation of the hydraulics was critical! Click for Animation

Municipal Wellfield

Flood Control Reservoirs

Transient Drawdowns



Case Study 4 – Mine Impact Assessment

29 - Case Study 4

Evaluated impact of future mine build- out

Multi-watershed model, but with high resolution around the mine site

Model represented open pit, waste rock stockpiles, drains, and tailings ponds

Model simulated drawdowns and change in streamflow from pre-mine conditions

Click for Animation



Case Study 5 – York Region Water Budget

Used an integrated model to assess the sustainability of wellfields that supply about 200,000 residents

30 - York Region

CMWR 2016

Watershed-Scale Integrated Modelling in a Canadian Context 31 - Case Study 5

Drawdown Impacts on Wetlands Percent Decrease in Baseflow

Under Future Pumping Study looked at effect

of drought on wells

Also looked at effect of wells on wetlands and coldwater streams

Study showed that streamflow affected mainly within 1-m drawdown line

Few wetlands and coldwater streams remained within 1-m drawdown

Case Study 5 – York Region Water Budget



CONCLUSIONS

32 - Wrap Up


Challenges in Integrated Modelling

33 - Wrap Up

Calibration ▪ Good calibration is mandatory for predictive, engineering studies

Model run times ▪ PRMS is fast but GSFLOW runs can take days

▪ Need faster MODFLOW solvers

▪ Better yet, need parallel solvers so models can run on multi-core machines

Model stability

Data limitations ▪ Continuous groundwater level and streamflow data can be sparse

Staffing ▪ Integrated, multidisciplinary teams are a must!


Overall Conclusions:

34 - Wrap Up

Integrated models are effective, practical tools to evaluate complex, challenging problems from the watershed to the engineering scale

Models provide insights for complex systems

Canada is moving ahead in the application of integrated modelling

There are ongoing challenges, but transient, integrated modelling is becoming the standard for impact assessments, water budgets, climate change predictions, drought assessments, and eco-hydrology studies

Click for Animation

Thermal transport from a gravel pit lake



Questions or Comments? Click for Animation

35 - Section Title


applications of integrated models to watershed and sub-watershed scale analysis: a canadian context

Engineering