Header link June 22, 2020

LinkedIn

  • Read more
Header link September 15, 2014

Cart

  • Read more
Header link November 3, 2015

Donate Now

  • Read more
Header link May 15, 2014

Twitter

  • Read more
Header link May 15, 2014

Facebook

  • Read more
Instagram
Header link May 15, 2014

Instagram

  • Read more
Header link May 15, 2014

Contact Us

  • Read more
More options
Water Education Foundation
Home

Water Education Foundation

Everything about California water that matters
  • Water Academy
    • Agriculture
      • Agricultural Conservation
      • Agricultural Drainage
    • Background Information
      • Legislation — California and Federal
      • Regulations — California and Federal
      • Water History
      • Water Rights
    • Bay-Delta
      • Bay Delta
      • Bay Delta Conservation Plan
      • Delta Issues
      • Delta Smelt
      • Sacramento San Joaquin Delta
      • San Francisco Bay
      • Suisun Marsh
    • Dams, Reservoirs and Water Projects
      • California Aqueduct
      • Central Valley Project
      • Folsom Dam
      • Friant Dam
      • Hetch Hetchy
      • Hoover Dam
      • Infrastructure
      • Lake Mead
      • Lake Powell
      • Oroville Dam
      • San Luis Dam
      • Shasta Dam
      • State Water Project
    • Environmental Issues
      • Anadromous Fish Restoration
      • Ecosystem
      • Endangered Species Act
      • Invasive species
      • Lake Tahoe
      • Mono Lake
      • Public Trust Doctrine
      • Salmon
      • San Joaquin River Restoration
      • Watershed
      • Wetlands
    • Leaders and Experts
    • Regions
      • Central Coast
      • Central Valley
      • Mexico
      • Nevada
      • North Coast
      • Pyramid Lake
      • Sacramento Valley
      • Salton Sea
      • San Joaquin Valley
      • Sierra Nevada
      • Southern California
      • Tulare Lake Basin
    • Rivers
      • Carson River
      • Colorado River
      • Klamath River
      • New River
      • North Coast Rivers
      • Russian River
      • Sacramento River
      • Truckee River
      • San Joaquin River
    • Water Issues
      • Climate Change
      • Coronavirus
      • Drought
      • Earthquakes
      • Energy and Water
      • Flood Management
      • Fracking
      • Growth
      • Hydropower
      • Levees
      • Tribal Water Issues
      • Water Conservation
      • Water Equity
    • Water Quality
      • Drinking Water
      • Nitrate contamination
      • Pollution
      • Stormwater
      • Wastewater
      • Water Quality
    • Water Supply and Management
      • Acre Foot
      • Aquifers
      • California Water Plan
      • Conjunctive Use
      • Desalination
      • Grey water
      • Groundwater
      • Integrated Regional Water Management
      • Recreation
      • Surface Water
      • Water Marketing and Banking
      • Water Rates
      • Water Recycling
      • Water Supply
      • Water Transfers
  • Tours & Events
    • Water Tours
      • 2023 Tour Sponsors
    • Events
    • Event Calendar
    • Past Tours & Events
      • Anne J. Schneider Fund Lecture Series
  • Specialized Programs
    • Water Leaders
      • Class Rosters
      • Yearly Class Reports
      • Your Alumni Network
      • Alumni Profiles
    • Project WET
      • Workshops
      • Special Workshops & Events
      • Supplementary Materials
      • California Content Standard Correlations
      • Facilitator's Trainings
      • Foundation School Programs
        • Elementary Programs
        • Secondary Programs
      • Water Kids
      • California Project WET Gazette
      • Gazette Archives
    • Colorado River Project
    • GRA Scholastic Fund Program
  • Maps & Guides
    • Maps & Posters
    • Layperson's Guides
    • Map & Guide Bundles
    • Books
    • Colorado River Materials
    • California Runoff Rundown
    • Other Publications
    • Water Awareness Materials
    • Downloadable Publications
    • Videos and DVDs
      • Video Clips
    • School Age Publications
    • Stickers
    • Free Programs and Publications
  • Newsroom
    • Western Water News
    • Aquafornia
      • About Aquafornia
    • Information Desk
    • Western Water Magazine Archive
      • Full Print Edition
      • Print Edition Excerpts
    • River Report Archive
  • Aquapedia
    • Alphabetical List of Subjects
      • A
      • B
      • C
      • D
      • E
      • F
      • G
      • H
      • I
      • J
      • K
      • L
      • M
      • N
      • O
      • P
      • Q
      • R
      • S
      • T
      • U
      • V
      • W
      • X
      • Y
      • Z
    • Historical Water People
    • Where Does My Water Come From?
      • Northern California
      • Sacramento
      • North Bay
      • South Bay
      • Central Valley
      • Los Angeles
      • Inland Empire
      • San Diego
      • All California Water Sources
    • Timelines
    • Videos
    • Image Gallery
    • Water Directory
      • Federal Agencies
      • State Agencies in California
      • Environmental Organizations
      • Other California Organizations
      • State and Federal Legislative Committees
      • Water Associations and Groups
      • Western States Water Agencies and Districts
    • Online Resources
    • Useful Acronyms
    • About Aquapedia
  • About
    • About Us
      • Board of Directors
      • Staff Biographies
      • Job Openings
    • Announcements
    • Support Our Mission
      • Become a Member
      • Donate in Honor/Memory
      • Donate to Aquapedia or Aquafornia
      • Shop Amazon
      • Planned Giving
    • Contact Us
Aquapedia background September 12, 2016

Runoff

Snowmelt and runoff near the California Department of Water Resources snow survey site in the Sierra Nevada east of Sacramento.Runoff is the water that is pulled by gravity across land’s surface, replenishing groundwater and surface water as it percolates into an aquifer or moves into a river, stream or watershed. It comes from unabsorbed water from rain, snowmelt, irrigation or other sources, comprising a significant element of the water cycle as well as the water supply when it drains into a watershed. Runoff is also a major contributor to the erosion that carves out canyons, gorges and related landforms.

The type, intensity and distribution of precipitation affects runoff, as does the slope, vegetation and topography of the land over which it travels. Climate change affects the patterns of runoff because as more precipitation falls as rain and less as snow, the snow melts faster as it is hit by rain. Furthermore, warmer temperatures change runoff patterns.

Wetter winters provide the opportunity to intentionally spread runoff onto fields to percolate into the aquifer, especially in the San Joaquin Valley’s overdrafted aquifers. However, getting water into those aquifers is hindered by the short time floodwater is available and the limited capacity of conveyance infrastructure to move water where it’s needed.

Urbanization has changed the dynamics of runoff by impacting the land itself. Infrastructure reduces the amount of permeable land into which water can absorb, causing more stormwater to pass over the surface, necessitating drainage systems to prevent flooding. The connection between wildfires and subsequent flooding has been attributed to the increased runoff that is unable to absorb into the scorched earth. Additionally, more pollutants like pesticides can be introduced as runoff flows over contaminated areas.

Runoff is a combination of surface runoff, interflow and baseflow:

  • Surface Runoff: Surface runoff comes from overland flow and saturation excess overland flow. Overland flow is from urban sources like roofs or pavement, while saturation excess overland flow is from precipitation or melted snow that simply could not be absorbed into the ground. Surface runoff from both of these sources is driven downhill by gravity.
  • Storm Interflow: Interflow usually comes about after a large amount of precipitation. It travels horizontally below the surface but above the water table, in an area called the “zone of aeration” or “vadose zone,”
  • Baseflow (aka Groundwater Runoff): Baseflow is the direct seepage from groundwater into surface water, which can bring with it whatever chemicals the groundwater has collected for thousands of years moving beneath the earth’s surface.
  • Print-friendly

Referring Pages

Share this page

  • Share on Facebook
  • Share on Twitter
  • Share on LinkedIn
  • Sent to a friend.
Print-friendly

Related Links

Aquapedia background September 12, 2016
Back
This item appears in:
  • Topic: Aquifers
  • Topic: Stormwater
  • Topic: Flood Management
  • Topic: Groundwater
  • Topic: Water Quality
  • Topic: Growth
  • Topic: Surface Water
  • Topic: Watershed
  • R
Footer pod May 20, 2014

Water Education Foundation

Copyright © 2023 Water Education Foundation. All rights reserved.

The Water Education Foundation is a nonprofit, tax-exempt, 501(c)3 organization, federal tax ID #942419885.

Privacy Policy

Donor Privacy Policy

  • Read more
Footer pod May 20, 2014

Contact Information

2151 River Plaza Drive, Suite 205
Sacramento CA 95833

Telephone (916) 444-6240

Contact Us via email

  • Read more

Quicklinks

Footer quicklink May 20, 2014

Contact Us

  • Read more
Footer quicklink May 20, 2014

Donate Today

  • Read more
Footer quicklink May 20, 2014

Tours

  • Read more
Footer quicklink May 20, 2014

Newsletter Signup

  • Read more
Footer quicklink May 20, 2014

Foundation News

  • Read more
Footer quicklink May 20, 2014

Calendar

  • Read more

Log in

  • Create new account
  • Request new password

Commands

  • Support portal
  • Log in