Introduction to and review of hydrologic / watershed Concepts
The Concept of Storm Water Management
Human Experiences with Storm Water
Storm Water and The Environment
What is Stormwater Runoff?
Think back to the water cycle…
STORMWATER simply refers to the various forms of
precipitation… it’s the water from the storm.
STORMWATER RUNOFF, is the surface runoff of
precipitation which has not infiltrated into ground or
surface storage reservoirs.
During or after the storm when PRECIPITATION in the form of rain
or snowmelt flows over the ground as RUNOFF.
The soil surface is incapable of absorbing more precipitation
The soil is already SATURATED
Or the ground surface is IMPERVIOUS
Surface reservoirs are at their capacity
Where does stormwater runoff go?
All Storm Water falls within a WATERSHED.
A watershed is an area of land from which all rainfall
drains to a common outlet point.
All land is a part of a watershed.
Watersheds can be very large--like that of the
Mississippi River --or as small as a street or
This diagram shows a
watershed in a
natural, undeveloped area.
It is important to visualize
the movement of water
into and through the
ground in addition to its
movement across the
surface in rivers and lakes
In a natural watershed, water
can infiltrate easily into the
ground, and this
groundwater is often
available for later use by
plants and people. Our area’s
water supply still comes
partly from pumped
Pollutants in an undeveloped
watershed do not become
concentrated and are easily
broken down by natural
processes in the ecosystem
(soil microbes and plants).
Here are the main
watersheds of the St. Louis
Small, local watersheds are
a part of larger watersheds.
The River Des Peres and
are parts of the Middle
Mississippi and Missouri
Since all of the watersheds
shown drain to the Gulf of
Mexico, they are all parts of
this much larger watershed.
• Stormwater can pick up debris, chemicals, dirt, and other
pollutants and deliver them to a storm sewer system or
directly to a lake, stream, river, wetland, or coastal water.
• Anything that enters a STORM SEWER system is
DISCHARGED untreated into the waterbodies we use
for swimming, fishing and providing drinking
When stormwater falls on
surfaces, it picks up
and carries with it a wide
variety of harmful pollutants.
• Impervious surfaces are
areas covered with
buildings or homes, streets
and parking lots as
opposed to ground
surfaces (soil, grass,
•The amount of
impervious area has a
direct relationship to
the quantity of
pollutants contained in
Pollutants from our cars, lawns, and pets build up as they wash quickly across the pavements, into
storm sewers, and into the ocean. As a result, our rivers and streams are usually not healthy places to
visit after a storm.
Leads to an increase in the intensity of Storm/Flood
events, increasing the flashiness of the system.
Human Experiences with
Loss of Life
Destruction of infrastructure
Public Health Concern
Beach / Lake closures
Bacterial / Viral infections
Loss of property
Loss of productivity
Stream bank failure
Stream channel incision
Accelerated sedimentation of aquatic habitats
Excessive algae growth
Oxygen Depletion/ Fish kills
Aquatic species contamination
Stormwater Management Requires
Remember, what sits on
the pavement often
makes its way to a
If it goes out your car
window, it often winds up
in a stream.
Increases in impervious
velocities, which increase
Case Study and Discussion
Is this a storm water problem?
Water Quality at the Lake of the Ozarks
Lake beach legislation still up in air
Measure would change how DNR tests, reports E.coli
By Ceil Abbott
Sunday, May 5, 2013
Despite assurances to the contrary, state Rep. Rocky Miller says he still isn’t sure if the Missouri
Department of Natural Resources will change its policy on testing for E.coli bacteria at state
park beaches, before the beginning of the tourist season.
Now, I’m being told to just leave my bill attached to House Bill 881, and when it comes across
the governor’s desk, the DNR won’t object to the changes, and it will automatically become
law,” Miller, R-Tuscumbia, said last week.
Miller was referring to a bill he introduced in the Legislature last January. It would change the DNR’s policy on testing
for high E.coli levels at state park beaches, and for closing those beaches to the public when the readings from those
tests are elevated.
The House Tourism and Natural Resources Committee took testimony on his bill on Feb. 14, but never recommended
it for full House debate.
The House passed the second bill on April 25, and it’s scheduled to be heard Tuesday by the Senate’s
Commerce, Consumer Protection, Energy and the Environment Committee.
To become law, both houses of the Legislature must approve the same language on a bill before 6 p.m. Friday, and
the governor has to sign that bill.
Under the terms of Miller’s bill, the DNR would be required to use the Environmental Protection Agency’s Method
1603, or an equivalent method, to determine if E.coli bacterial levels at state park beaches are too high for public
The DNR would be required to take several samplings of the water at public beaches over a 30-day period. Then, if
the test results consistently exceed the EPA-established geometric mean standard for public safety, the DNR would
post a sign reading, “Swimming Not Recommended” rather than using “yellow crime scene tape” to close the
beach, Miller said.
Miller sought input from the DNR when writing the legislation, and his language reflected their recommendations.
He said he also received a promise from the DNR that the agency would change its testing policy to reflect safety
standards set by the federal government more directly.
Miller said he wrote the bill because “Missouri has the strictest standards for E.coli levels of any state in the
nation, and even exceeds the levels the EPA considers safe for public use.”
The Tuscumbia Republican said he had been contacted by a number of business owners and tourism organizations that
believe the DNR’s beach closure policy is damaging the economy in tourist areas.
Jim Divincen, Tri-County Lodging Association administrator, was one of the lake area representatives who expressed
concern about the effect of the DNR’s policy on the local economy. When the DNR closes a beach because of elevated
E.coli levels, it often gives visitors the idea that the water quality in the entire lake presents a health hazard, Divincen said.
“As important as it is that the method of testing be changed, it is equally important that the DNR change the way in which
it notifies the public of a beach closing,” Divincen said.
In March, Divincen and others testified before the House Committee on Tourism and Natural Resources in Jefferson City.
“The last lakewide sampling conducted on the Lake of the Ozarks, based on 285 samples from areas around the lake, has
proven scientifically that the Lake of the Ozarks is one of, if not, the cleanest bodies of water in the state, in terms of
bacteria.” Divincen said.
In mid-April, Miller said DNR personnel told him the testing policy would be changed and that signs would be used when a
beach was closed.
He was told the policy would be in effect before state park beaches open on Memorial Day weekend.
Bill Bryan, the DNR’s director of state parks, did not return phone calls seeking a comment for this story.