Hydrology
Emojis Have Meanings to Guide You!
📚--->Supplemental Resource!
📚 Picture above is the Au Sable River, a National Scenic River.
What does the term mean?
Definition
"Hydrology is the science that encompasses the occurrence, distribution, movement and properties of the waters of the earth and their relationship with the environment within each phase of the hydrologic cycle." -US Geological Survey
Noting that some things we covered in Climate and Weather would also fall under Hydrology. The Great Lakes Literacy Principles section covers the occurrence and distribution of freshwater on the earth.
In Focus: Lake Huron Watershed and Your Place
Movement Into Atmosphere by Water Bodies
Evaporation (water's change from liquid to gas) off water bodies - oceans, lakes, rivers - accounts for almost 90% of the moisture in our atmosphere.
📚 Refresh yourself on the process here!
📚 Learn more about just how much water is evaporating off the Great Lakes.
Movement Into Atmosphere through Soil and Plants
Evapotranspiration
(The combined effect of transpiration and evaporation)
Utilizing the USGS definition, we'll define evapotranspiration as "the sum of evaporation from the land surface plus transpiration from plants".
📚 This page provides a full overview of this process.
Image Source: Agriculture Victoria
Canopy Interception
The tree canopy in any given area will significantly impact how much water moves directly back to the atmosphere and how much is able to reach the ground for plant uptake. The video below provides more information on canopy interception (to the 1:30 mark).
📚 Review this paper's introduction to understand why measuring canopy interception is difficult and how models can help us understand this.
Movement Across Landscapes
The Great Lakes Literacy Principles section covers watershed in full, feel free to reference back to that for a full watershed overview. Here we'll review some ways that water shapes landscapes.
Moving Surface Water
Through erosion and deposition, moving surface water - rivers, streams, creeks - can form new land elements or change their courses. Similar processes happen on lake shores. Water speed and particle size, which will be explored in Soil section, impact this process.
Moving Groundwater
Groundwater - found in pores and cracks in soil and rock underground - moves and is stored in aquifers. When we talk about the water table, this refers to the top layer of the saturated zone of aquifers.
This document identifies the bedrock aquifer type of areas in Michigan (pg. 1 figure). The average groundwater component of the some Michigan streams is also covered (Figure 11, pg. 10 in document, 15 per PDF count at top).
Movement Across and Into Various Materials
Surface Runoff and Stormwater
These two terms are often used interchangeably and for our purposes can be as well.
Surface runoff accounts for much of the recharge of our surface waters following precipitation events (rainfall or snow-melt). Because of the speed that water can gather as it moves across a surface, runoff also helps shape our land through erosion. Stormwater is typically related to our built environment and how humans cause runoff to behave differently than it naturally would.
This 2-minute video provides an overview of stormwater impacts.
Types of Surfaces
Surfaces can be categorized as permeable (allowing water to flow through) or impermeable (not allowing water to flow through). You may also see the terms pervious and impervious. Note that sometimes highly compacted soils, soils typically being considered permeable, may actually be impermeable.
Infiltration
Infiltration - downward movement of water from the ground surface into soil and groundwater - contributes to plant and fungi growth as well as groundwater recharge. The rate of infiltration is impacted by variables such as the slope of an area, land use, and soil type and saturation.
Seepage
As gravity moves water both down and through permeable soil, seepage can occur. It contributes to recharge of surface water bodies during droughts. It may also occur in developed areas where the surface has been dug out below the water table height.
Note on language: seepage is an aspect of subsurface flow. Overland flow is another term for runoff.
Image Source: Idaho State University
Image Source: Center for Watershed Protection
Wetlands
From spawning grounds to water filtration services, wetlands play a vital role in the water cycle and health of all living things. There are currently about 6.4 million acres of wetland habitat in Michigan.
This mapping tool provides location and classification information on federally designated wetlands. By clicking on the colored area, you'll be able to read more about any wetlands present in an area of interest.
📚 Learn more about the loss of wetlands in Michigan since European settlement with this 4-minute radio spot.
Image Source: Toronto and Region Conservation Authority
👥 Community Partner Connections 👥
Who are some of the partners that focus on Hydrology in the Great Lakes basin and Michigan?
✅ Michigan Sea Grant
📚 Brandon and Meaghan can help connect you! Check out great data sets on Great Lakes hydrology.
✅ U.S. Army Corps of Engineers
📚 Find contact information and more about what they do here.
✅ MI Department of Environment, Great Lakes and Energy
📚 Find contact information and more about what they do here .
✅ Huron Pines
📚 Emily can help connect you! Learn more about Huron Pines' Healthy Water Program.
✅ U.S. Fish and Wildlife Service
📚 Find contact information and more about what their aquatic connectivity efforts in the Lake Huron watershed..
✅ U.S. Forest Service
📚 Find contact information and more about what their aquatic passage program. .
