1 Stream Functions

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Introduction to Watersheds Hydrology Water
Quality
Watershed Academy Greg Jennings, PhD,
PE jennings_at_ncsu.edu
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"We have to teach the general public to
appreciate water - clean water - both in quality
and quantity. The American people take it for
granted. We can't take it for granted. "We
can solve many of our problems in water quality
by good land management, taking care of the
watershed. Luna Leopold, 2002 Retired Chief
Hydrologist, U.S. Geological Survey
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• 1948 Federal Water Pollution Control Act (FWPCA)
  "enhance the quality and value of our water
  resources and establish a national policy for
  prevention, control and abatement of water
  pollution"
• 1956 Water Pollution Control Act Amendments
  allow federal government to act where health
  endangered
• 1965 Water Quality Act enforceable water quality
  standards
• 1972 FWPCA Amendment (Clean Water Act)
  consolidated authority in EPA with objective
  restore and maintain chemical, physical, and
  biological integrity of nation's waters
• Goals
• (1) eliminate discharge of pollutants into the
  navigable waters of the United States by 1985
• (2) water quality that provides for the
  protection of fish, shellfish, and wildlife and
  recreation by 1983.

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• From Webster's Revised Unabridged Dictionary
  (1913)
• Watershed, n Cf. G. wasserscheide wasser water
  scheide a place where two things separate, fr.
  scheiden to separate.
• The whole region or extent of country which
  contributes to the supply of a river or lake.
• The line of division between two adjacent rivers
  or lakes with respect to the flow of water by
  natural channels into them the natural boundary
  of a basin.
• Other Terms Catchment, Drainage basin, River
  basin

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Watershed

• Area of land that drains water, sediment, and
  dissolved materials to a common outlet at some
  point along a stream channel
• Dunne and Leopold, 1978
• Watershed form is influenced by
• Climate
• Geology Soils
• Fluvial Geomorphology
• Vegetation
• Land Uses

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Watershed Functions

• Transport Storage
• Water
• Sediment
• Dissolved Materials
• Habitat
• Animals
• Plants
• Humans

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Water Transport Storage
Hydrology The study of the flow of the earths
waters through the hydrologic cycle. Total Water
on Earth 326 million cubic miles 97.2
oceans 2.15 ice caps and glaciers .65 lakes,
streams, ground water, atmosphere
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The Hydrologic Cycle
Stream Corridor Restoration Principles,
Processes, and Practices. 1998. Federal
Interagency Stream Restoration Working Group.
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Hydrologic Cycle

• The flow of water through the earths system,
  powered by gravity and solar energy.
• Precipitation
• Evaporation
• Evapotranspiration
• Surface Runoff
• Stream Flow
• Infiltration
• Subsurface Flow
• Ground Water Flow

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Hydrologic Responses to Urbanization

• Increased discharge
• Increased peak discharge
• Increased velocities
• Shorter time to peak flow
• More frequent bankfull events
• Increased flooding
• Lower baseflow
• Less ground water recharge

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Hydrograph Changes Due to Urbanization
Urban
Rural
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Sediment Transport Storage

• Flowing water does work
• Erosion
• Sediment Transport
• Sediment Deposition
• Channel Development
• Channel Adjustments

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Stream Corridor Longitudinal Profile
Stream Corridor Restoration Principles,
Processes, and Practices. 1998. Federal
Interagency Stream Restoration Working Group.
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Sediment Sources

• Land Disturbance
• Channel Erosion
• Bedload Transport

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• Stream Functions
• Transport water
• Transport sediment
• Habitat (aquatic terrestrial)
• Recreation
• Aesthetics
• Safe Water Supply

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Stream Corridor Lateral Profile
Stream Corridor Restoration Principles,
Processes, and Practices. 1998. Federal
Interagency Stream Restoration Working Group.
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Stream Channel Cross-Section
Stream Corridor Restoration Principles,
Processes, and Practices. 1998. Federal
Interagency Stream Restoration Working Group.
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Ephemeral

• Intermittent

Perennial
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Strahler Stream Order
Stream Corridor Restoration Principles,
Processes, and Practices. 1998. Federal
Interagency Stream Restoration Working Group.
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Stream Channel Morphology
size and shape of the channel

• Influenced by
• Watershed area
• Land use and land cover
• Soils and geology
• Topography
• Climate
• Human impacts (intentional or not)

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Stream Components
Terrace
Floodplain
Right Bank
Left Bank
Thalweg
Streambed
Downstream
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Stable Stream

• transports the water and sediment produced by
  its watershed, such that over time it maintains
  its dimension, pattern, and profile, while
  neither degrading nor aggrading
• Rosgen, 1994

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Water Quality

• Influenced by
• Geology Soils
• Land Use
• Pollution Sources
• Flow Conditions

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Stream Impairment Causes (EPA, 2000)

• Sediment
• Pathogens
• Nutrients
• Metals
• Dissolved Oxygen
• Habitat Alterations
• Temperature
• pH
• Impaired Biology
• Pesticides
• Flow Alterations
• Mercury

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Where Does PollutionCome From?
Nonpoint Sources
Stormwater
Agriculture
Point Sources
Forestry
Construction
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Point Sources

• Wastewater Treatment Plants (WWTPs)
• Industrial Plants
• Sources of organic waste, nutrients, pathogens,
  metals, chemicals
• Regulated by federal Clean Water Act (EPA)
• National Pollutant Discharge Elimination System
  (NPDES)
• Permitted limits of discharges
• Regular monitoring inspections
• Fines for permit violations

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Agriculture Livestock Production

• Sources of nutrients, pathogens, organic waste,
  habitat loss
• Regulated by numerous state federal laws
• Farm Bill
• Clean Water Act
• State Local Regulations

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Agriculture Crop Production

• Sources of sediment, nutrients, pesticides,
  habitat loss
• Regulated by numerous state federal laws
• Farm Bill
• Clean Water Act
• Pesticide Regulations
• Nutrient regulations

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Forestry

• Commercial Timber Production
• Small Woodlot Forestry
• Sources of sediment, nutrients, habitat loss
• Regulated by Sediment Pollution Control Act
• Forestry BMPs required
• Technical assistance from NC Div Forest Resources
• Financial incentives for forest management

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Urban Stormwater Construction

• NC population doubles every 40-50 years
• Urbanized area doubles every 20 years
• Sources of sediment, nutrients, pathogens,
  metals, chemicals, pesticides, habitat loss
• Regulated by Clean Water Act
• Phase 1 and 2 NPDES regulations
• Limits on development
• BMPs required

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Land Development Impacts

• Increased Imperviousness
• Increased Runoff
• Increased Pollutants
• Impacts to Streambanks
• Erosion/Sedimentation

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Stream Condition Related to Impervious Surface
Good Fair Poor
Protected
Impaired
Urban Drainage Network
Degraded
Source Center for Watershed Protection
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ChallengesWater quality problems

• Watershed-scale
• Result from many diffuse sources
• Difficult to diagnose
• Related to local land uses