WATERSHEDS 101

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WATERSHEDS101

• Prepared by Ernie Ewaschuk,
• Land Stewardship Centre of Canada
• August 2005

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ACKNOWLEDGEMENTS

• Hans Schreier, Ken Hall, Sandra Brown, Les
  Lavkulich and Paul Zanbergen.
• Integrated Watershed Management
• Institute for Resources and Environment-Universit
  y of British Columbia
• Mark De Villiers, WATER
• Sandra Postel, Rivers for Life
• Sarah Primeau, Land Stewardship Centre of Canada
• Land Stewardship Centre of Canada

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Presentation Outline

• Watershed Definition
• Watershed Characteristics
• Watershed Approach
• Hydrologic Cycle
• Role of Wetlands in the Watershed
• New Approaches/Challenges
• Conclusions
• Land Stewardship Centre of Canada

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WATERSHED CONCEPT NOT NEW!
"The Watershed is the most logical unit for
resource planning and land use decision
making..." This was the wise observation of John
Wesley Powell in his report to Congress in
1877. If Congress had listened to explorer and
scientist John Wesley Powell 125 years ago, the
American West today might be an entirely
different place. "We would not have, if
Powell's ideas had carried through, any of our
huge federal water projects," says Powell
biographer Donald Worster. "And we certainly
would not have had anything like the massive
urban growth that's taken place in the West." In
1878, Powell published his Report on the Lands of
the Arid Region, which laid out a concrete
strategy for settling the West without fighting
over scarce water. "For Powell, the water would
not be taken out of the watershed or out of the
basin and transferred across mountains hundreds
of miles away to allow urban growth to take
place. http//www.npr.org/programs/atc/features/2
003/aug/water/part1.html Land Stewardship
Centre of Canada
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Watershed Definition

• An area of land, bounded by topographic
  features, that drain water to a shared
  destination such as a lake, stream, estuary, or
  ocean. A watershed captures precipitation,
  filters and stores water and determines its
  release.
• Hans Schreier, Ken Hall, Sandra Brown, Les
  Lavkulich and Paul Zanbergen.
• Integrated Watershed Management
• Institute for Resources and Environment-Universit
  y of British Columbia
• Land Stewardship Centre of Canada

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Watershed Diagram
Watershed and watercourse are different! We all
live in a watershed! We all impact the
watershed! We all must be part of the
solution! Adapted from Schreier et
al Land Stewardship Centre of Canada
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Watershed Characteristics

• Watersheds divide the landscape into hydrological
  defined geographic areas
• Watersheds integrate all environmental functions
• Physical, chemical, biological, human use, and
  management determine water quality and water flow
• Each watershed has a unique combination of
  inherent conditions, use, and management, thus
  response to water quality and flow is variable
  and complex

Land Stewardship Centre of Canada
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Watershed Use

• What we do on the landscape impacts on water
  quality and quantity
• Land use determines how we store water, release
  flows, add nutrients, chemicals, etc.
• Our impacts are felt downstream just as we are
  affected by what happens upstream

Land Stewardship Centre of Canada
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WATERSHED IMPACTS

• Excess of nutrients from the land, leads to
  excessive plant growth in aquatic systems
• As the plant growth decomposes it uses up oxygen
  that organisms require
• System can then become dead zone
• Some are now equating Lake Winnipeg to the
  condition Lake Erie was in the 1960s
• Photo - Schreier et al

Land Stewardship Centre of Canada
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WATERSHED IMPACTS

• Fertilizers, pesticides, organic matter and
  hydrocarbons all find their way into aquatic
  systems via storm sewers
• More recently, pharmaceuticals, hormones and
  other compounds are being detected in our waters
• Many of these substances are slow to breakdown
  and tend to accumulate downstream
• Photo - Schreier et al

Land Stewardship Centre of Canada
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Nutrients from the Watershed

• Dams, levees, channelization have severed the
  river-floodplain connection
• Rivers have lost ability to purify water as they
  move through the watershed
• Rivers then carry these heavy nutrient loads to
  the ocean, i.e. Gulf of Mexico has developed a
  dead zone from excessive algal blooms Lake
  Winnipeg is going in this direction as well
• With loss of wetlands, through drainage, more
  nutrients runoff into streams and rivers

Land Stewardship Centre of Canada
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Watershed Approach

• Identifying issues and objectives
• Data collection and analysis
• Synthesis
• Planning
• Decision making
• Implementation
• Monitoring

Land Stewardship Centre of Canada
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Hydrologic Cycle

• Supply of earths water is constant (fixed)
• 97 is too saline for human use
• 3 is fresh water
• 75 of the fresh water is in ice caps and
  glaciers
• 25 is groundwater
• 0.3 of fresh water is in lakes and reservoirs
• 0.003 of fresh water is in rivers
• Water moves around through the Water Cycle
• Includes precipitation, evaporation,
  evapo-transpiration, condensation, infiltration,
  percolation, storage, runoff, and overall water
  balance

Land Stewardship Centre of Canada
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Diagram - Schreier et al
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Watershed Storage

• Groundwater
• soil
• Shallow groundwater
• Deep aquifers
• Surface water
• Rivers, lakes, reservoirs, wetlands
• Atmosphere
• Photo - Schreier et al

Land Stewardship Centre of Canada
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Diagram - Schreier et al
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Role of Wetlands in WatershedNOT SO OBVIOUS
BENEFITS

• Shallow Groundwater Recharge
• Increased Soil Moisture
• Deep Aquifer Recharge
• Nutrient Filtering
• Flow Stabilization
• Local Weather Effects
• Economic Wetland Values

Land Stewardship Centre of Canada
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Wetlands in the Watershed
Conceptual diagram of shallow groundwater flow
Approximate area of increased soil
moisture (sub-irrigation)
Infiltration to adjacent uplands
Infiltration to shallow groundwater
Percolation to deep groundwater - aquifer
Land Stewardship Centre of Canada
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Nutrient Removal by Wetlands
Land Stewardship Centre of Canada
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WETLANDS REDUCE FLOOD PEAKS (HYPOTHETICAL CASE)
Local surface flow water is stored in wetlands
during spring runoff and periods of high flow
Regional groundwater flow releases water slowly
into stream throughout season, maintaining flows
longer
Land Stewardship Centre of Canada
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WETLANDS REDUCE FLOOD PEAKS (HYPOTHETICAL CASE)
With no wetlands to store local surface flow
water runs into drainages all at once causing
flooding downstream.
Little or no water is stored for later release
causing stream to stop flowing early
Land Stewardship Centre of Canada
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Time
Natural Flood
Natural Flow Pattern
Natural High Flows
River Flow
Natural Low Flows
Time
Dam-Altered Flow Pattern
River Flow
Land Stewardship Centre of Canada
Adapted from Postel (2003)
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Natural Flow Pattern
Natural Flood
Natural Low Flow
Dam-Altered Flow Pattern
Inadequate Low Flow
Absence of Flood
Land Stewardship Centre of Canada
Adapted from Postel (2003)
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Wetlands - Local Weather Effects

• Evaporated surface water from wetland and
  transpiration from trees are sources of water
  vapour to atmosphere
• Water vapour condenses in the cooler atmosphere
  initiating locally generated circulations that
  produce moist convection i.e. cumulus clouds,
  thunderstorms and local/regional precipitation
• Atmospheric circulation patterns affected by
  area, depth, and distribution of wetlands
• May have profound effect on climate of adjacent
  communities
• Water surfaces, such as wetlands, have high
  thermal inertias (slow to heat/cool), and have a
  moderating effect on local temperature
  maintaining lower temperatures in summer and
  increase minimum temperatures during cooler
  periods
• Example agricultural area drained of wetlands
  was as much as 5oC colder than surrounding wet
  (less drained) areas

Land Stewardship Centre of Canada
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Condensation (cloud formation)
Precipitation
Transpiration
Evaporation
Land Stewardship Centre of Canada
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Economic Wetland Values

• As economists determine the value of wetlands to
  the ecosystem, the sum of the benefits provided
  outweigh the costs to maintain
• Study in Sask. found net loss -1596 in
  converting 5 acres of wetland to crop production
  over a ten-year period (added costs associated
  with drainage outweighed added revenue received)
• Study calculated that the annual cost benefit
  associated with
• Draining cultivation of wetlands 36.74/ha
• Wetland recreational value (wetlands in natural
  state)
• 1,490/ha for Sask. 3,140/ha for
  Sask. U.S.A.
• Calculated cost of flood control 300/acre foot
• Values placed on wetland services have ranged
  from 0.06 to 22,050 per acre (US) in 33 studies
  over the past 26 years
• Average global value of ecosystem services
  provided by wetlands 14,785/ha/yr
  cropland 92/ha/yr
• USA study calculated the benefits of the
  floodplain for fuelwood, agriculture and fishing
  _at_9,600-14,500 compared to 26-40/cubic metre
  for irrigation (Postel)

Land Stewardship Centre of Canada
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PHILOSOPHY Concept
Approach Focus

• Anthropogenic focus on econ. dev.
  human domination over nature
• resource exploitation
• environ. protection
  end of pipe, damage control
• resource mgmt
  green movement incorporate risk
• econ. dev. does not help
  everyone

Land Stewardship Centre of Canada
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SHIFT IN APPROACHES

• NEW
• Human impacts have serious and long term effects
• Multi-dimensional problems
• Long term human health concerns
• Effects include interactions among users and
  non-point source
• Meso - macro scale (watershed/landscape)
• Time scale is 5-10 years
• Management is pro-active, preventative,
  anticipate problems
• Multi-stakeholder participation
• Focus on multiple solutions

OLD

• Economic development comes first
• Uni-dimensional (one industry/sector)
• Single pollutant health effects (LD50)
• End of pipe or dilution solution
• Site specific
• 1-2 years
• Reactive, crisis management
• Specialist being the dominant
• Focus on single solution

Land Stewardship Centre of Canada
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Challenges

• Combining social values and scientific
  understanding (both are changing mgmt needs to
  be adaptive)
• Documenting multiple source problems over time
  and scale
• Addressing resistance and
• resilience of watersheds
• to change
• Living within the means
• of our watershed
• Adapted from Schreier et al

Land Stewardship Centre of Canada
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WATERSHED INDICATORS

• How do we recognize an unhealthy watershed?
• Poor water quality
• Lack of bank vegetation
• Fish are no longer able to survive
• Forage production decreases
• Rapid runoff causes damage
• Signals from downstream users

Land Stewardship Centre of Canada
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WATERSHED RESTORATION

• What can we do about it?
• Problem is not new
• Others have gone through these problems
• Opportunity to benefit from what others have done
• What works, what doesnt

Land Stewardship Centre of Canada
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WATERSHED BENEFITS

• What does a healthy watershed provide for us?
• Clean air and water
• Healthy people and communities
• Healthy and sustainable economy
• Flood reduction (water storage)
• Supports a diversity of plants animals
• provides recreational opportunities

Land Stewardship Centre of Canada
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Watershed Approach - Summary

• Water is essential to all life on earth!
• We all live in a watershed!
• We all live upstream/downstream!
• Everything we do on the land affects our
  watershed
• We all have a responsibility to care for our
  watershed
• A Watercourse is not a Watershed!

Land Stewardship Centre of Canada
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Watershed Management Golden RuleTALK AND
LISTEN

• Talk to people upstream!
• BUT
• Listen to people downstream!

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