Field Biology Packet
Soils # 9
BEST MANAGEMENT
PRACTICES (BMP) OF
CONSTRUCTION SITES
BACKGROUND INFORMATION
Running water carries many substances. Frequently running water can carry soil, gravel, and even
large rocks. If you have ever been near a waterway after a flood, you might even have seen
refrigerators being carried along by the flood waters.
As running water is made to slow down or is slowed naturally, the material carried by the water drops
out. As a river reaches the Chesapeake Bay, or when any river begins to merge with a larger body of
water, the rate of flow slows down a little. At the head of the Chesapeake Bay, where the
Susquehanna River meets the Bay, is an area called the Susquehanna Mud Flats. The Susquehanna
River slows down as it reaches the Bay and dumps much of its load-sand, silt, clay. The area that
forms is called a mud flat.
Construction sites provide another example of soil that is “free to roam”. At the beginning of a
construction project, the area is often stripped of its vegetation leaving the soil exposed to the
atmosphere and weather. When it begins to rain, the exposed soil is carried away and eventually
reaches streams or rivers. The soil makes the flowing water very turbid. Turbidity also coats the
leaves of underwater plants; which in turn, can kill the plants because they can no longer undergo
photosynthesis. When the plants die, the aquatic food web is grossly affected.
The next time you walk by a construction site, examine what you see. Erosion is inevitable when rain
hits construction sites. Can anything be done to prevent this MUD POLLUTION? Do construction
companies follow any regulations?
OBJECTIVE
The student will be able to use a reading strategy in order to collect BMP for construction sites.
MATERIALS
Article, “Evaluation of Construction Sites for Sediment Control Compliance”
SQ3R reading strategy or list of questions for comprehension or Anticipation Guide
333
Field Biology Packet
Soils # 9
PROCEDURE
1. Observe a picture on your desktop and explain what is happening.
2. Read the article given to you using a technique explained to you by the teacher.
3. Complete homework working with a parent or a friend.
ANALYSIS (B)
“EVALUATION OF CONSTRUCTION SITES FOR
SEDIMENT CONTROL COMPLIANCE”
Answer the following questions by writing complete sentences. The sentences should include
parts of the question to begin the answer. Use a separate piece of lined paper for your answers.
Staple these pages together along with this question sheet.
1. How does mud pollution rob shipping channels of depth?
2. Which government – federal, state, or county- is responsible for enforcement of soil
control issues involving construction sites?
3. Which state is responsible for the law that was enacted in 1970?
4. What is the purpose of erosion control technologies? Name three of the most frequently
used measures. How effective are they?
5. What must any contractor do before beginning a project?
6. What are the two approaches to controlling construction site erosion?
7. Explain how basins and traps are related; how are straw bales and silt fences related?
8. Where are perimeter control devices located and WHY?
9. There are three temporary stabilization measures. Name them.
10. Who is the enforcer of erosion control on construction sites?
11. What one word makes perimeter controls and temporary stabilization effective?
12. How frequently are sites evaluated?
13. How are infractions reported to the construction site boss? If infractions are not corrected,
what happens?
14. What portion of a construction site requires temporary stabilization?
15. There are two answers to #6 above. Which of these is usually attempted on construction
sites? Why do you think the other is often left undone?
334
Field Biology Packet
Soils # 9
“EVALUATION OF CONSTRUCTION SITES FOR
SEDIMENT
CONTROL COMPLIANCE”
I. INTRODUCTION
Mud from exposed construction site soils may have damaged as much as 1,900 miles of
Maryland waterways. It is one of the major problems for the Chesapeake Bay. In the next 40
years, Maryland could lose another 700 miles of waterways due to future construction activity. It
will take those waterways a century to fully recover from the ravages of construction site derived
mud pollution.
II. CONSTRUCTION SITES ARE A PROBLEM
Sediment running from the typical construction site of about 20 acres, damages three to five
miles of waterway below the site. Mud pollution is as dangerous to aquatic life as cyanide or
DDT, requiring 10-100 years to restore degrading waters. Mud pollution aggravates flooding and
robs boating channels of depth, and reservoirs of storage capacity. Generally, for every dollar
spent keeping mud on a construction site, the public will be spared a minimum of $83 in
damages.
III. WHAT STATE TOOK AN INITIATIVE?
Since 1970, Maryland law has required builders to use measures to control soil erosion and to
trap soils where erosion occurs on the construction site. With few exceptions,
enforcement of this law on residential, commercial, and industrial
construction sites is the responsibility of state, county, and city governments.
The state enforces sediment control on its own projects, mining operations,
and in all counties and municipalities that have not been delegated
enforcement power.
IV. EROSION CONTROL MEASURES
The technologies of erosion and sediment pollution control began in Maryland. These
technologies are among the simplest of all pollution-control measures. Erosion control is
designed to prevent soil from eroding. The most frequently used erosion control measures
include: mulching exposed soil with straw, putting down temporary grass seeding and/or clearing
only those portions of the site that will be developed in the near future. Erosion control measures
can reduce off-site sediment (mud) pollution by up to 90% when used properly. Erosion can also
be controlled through administrative land-use decisions that restrict or prohibit disturbance of
highly erodable soils.
Prior to disturbing the earth, the builder must submit a sediment control plan for the approval of
local sediment control authorities. Before construction can begin, that sediment control plan must
meet Maryland’s Standards and Specifications. By law, the sediment control plan will call for
two approaches to minimizing off-site soil loss.
335
Field Biology Packet
Soils # 9
V. TWO WAYS TO MINIMIZE OFF-SITE SOIL LOSS
The first approach is perimeter control. This approach relies on the use of various devices to
slow the velocity of the running water and to capture the sediment. Basins and traps are
essentially holding ponds for running water and they rely on the process of settling to control soil
loss. Straw bales and silt fences filter the running water as it passes through, removing the
sediment and holding it on the site.
Perimeter control devices are located at the lowest
point of the site, which is usually along the
downslope perimeter of exposed soils. A system
of ditches, dikes or swales can be used to divert
running water to these devices. The devices are
designed to store the settled particles of sediment.
Perimeter control can stop 50-70% of the eroded
soils from leaving the site. The effectiveness will
vary according to many factors including the
tendency of the soil to erode, the degree of slope of the site, and the condition of the devices
themselves.
The second approach is known as temporary stabilization. Temporary stabilization measures are
designed to reduce the susceptibility of soil to erosive forces. The best type of sediment control
is natural ground cover – trees, shrubs, and grass. The next best is temporary seeding and
applying straw mulch so that no bare exposed soil shows through the mulch.
Total coverage is important because the mulch serves to lessen the impact of rain as it strikes the
ground – mulch will slow down the flowing precipitation as it follows its course through
previous erosion channels (remember slowing moving water makes the water dump its sediment
load), and mulch will filter the water holding back the soil but allowing most of the water
through. Mulching can reduce mud pollution by 95%. Work areas where mulching is not
practical, such as roads and access points, should be covered with crushed rock. Temporary
stabilization is required on all exposed soils not currently undergoing grading and is much more
effective than perimeter controls alone. The higher level of effectiveness makes temporary
stabilization the most desirable method of controlling sediment pollution.
VI. STATE LAW REQUIREMENTS
Once the plan is approved, the builder can begin site development. State law requires the builder
to ensure that one employee is trained in sediment control. This person must become certified in
erosion control by successfully completing an erosion and sediment control training program. It
is this person’s responsibility to check required erosion and sediment control measures at the end
of each work day and make certain that each measure is in proper working order.
Maintenance is the key to the effectiveness of both perimeter controls and temporary
stabilization. Both measures require constant attention. Old fences and straw bales may wear out;
basins and traps may need to be emptied; a temporary seeding might not germinate the first time.
Sediment control enforcement authorities must visit each major
construction site at least once every two weeks. The enforcement
authority may represent a city, county, or state. The inspector walks the
336
Field Biology Packet
Soils # 9
entire site to determine whether the builder is in fact complying with the approved sediment
control plan.
VII. WHAT HAPPENS WHEN NON-COMPLIANCE CONTINUES?
If deficiencies are found, the builder is given a written order to correct them. If the builder fails
to make the necessary repairs within a specified time period, the inspector may issue a “Stop
Work Order”. This order halts all work on the site except that necessary to correct the violations.
Despite this rather comprehensive and sophisticated program, surveys have shown that only 15%
to 25% of all active construction sites fully comply with sediment control standards. While there
has been substantial improvement in the rate of compliance for perimeter control and sediment
trapping devices, the level of temporary stabilization has remained very low. This situation
allows thousands of tons of mud to needlessly pollute our waterway each year. While the reasons
for this high rate of non-compliance are complex, we do know that active citizen involvement
consistently results in greater use of control measures on construction sites.
VIII. CONCLUSION
Citizens tend to rely on government to enforce water quality regulations, but the job is too big for
government alone. The Chesapeake Bay and its troubled tributaries will only recover when
citizens join the campaign for a cleaner marine environment. The goal is to obtain a high level of
compliance with sediment control requirements. To do this, regular evaluation of construction
sites for compliance with mud control standards and reporting non-compliance to sediment
control authorities is needed.
Part of the evaluation assesses the use of perimeter control devices. The rest examines the
utilization of temporary stabilization measures. The first step in this evaluation is to estimate the
percentage of each site which is bare exposed soil. That is, the percentage of the site which has
been disturbed by the construction, but is not currently being graded, and is not covered by
buildings, foundations, crushed rock, paving, planted grass, straw mulch, or natural cover. This is
the portion of the site which requires temporary stabilization measures.
337
Field Biology Packet
Soils # 9
ANALYSIS (A)
#
SUBTITLE
I
SQ3R
QUESTION
READ/ANSWER
II
III
IV
338
Field Biology Packet
Soils # 9
V
VI
VII
VIII
339
Field Biology Packet
Soils # 9
ANALYSIS (C) Anticipation Guide
“EVALUATION OF CONSTRUCTION SITES FOR SEDIMENT CONTROL COMPLIANCE”
Directions: Before reading, think about whether or not you agree with the statements, and place a check in the appropriate box under
the “Before Reading” heading. After reading, think about the information you read and whether or not it changed your opinion about
any of the statements about the topic. Then place a check in the appropriate agree/disagree box under the “After Reading” heading.
Finally, if your check is in the disagree box after reading, alter the statement so that you will agree with it. Write your changes clearly
within the central box of this table.
Before reading
Agree Disagree
After reading
Statements about the Topic
Construction site pollution is limited mainly to particulate “dust” air pollution.
Cyanide poisoning is one of the most dangerous aquatic pollutants.
California is the leading state in the USA that has incorporated construction site compliance
laws.
Erosion control is designed to prevent soil from eroding. Three frequently used measures are
covering exposed soil with straw, adding grass seeds to the exposed soil, and clearing only
small portions of the site as needed.
Perimeter control is when an assigned construction worker walks the edges of the construction
site to monitor whether soil runs into the streets or surrounding properties.
340
Agree
Disagree
Field Biology Packet
Soils # 9
Before reading
Agree Disagree
After reading
Statements about the Topic
Temporary stabilization of a construction site is expensive because ground cover is to be left
intact with no exposed soil and/or crushed rock is to be covering areas where soil could easily
be worn away (areas where heavy machinery enters the site and/or pathways that are used
extensively throughout the work day).
Sediment control authorities will visit construction sites once a month.
Constant review of the construction site by sediment control authorities is the key to
effectiveness of both perimeter controls and temporary stabilization controls.
Surveys have shown that nearly 65% of all construction sites fully comply with sediment
control standards.
341
Agree
Disagree
Field Biology Packet
Soils # 9
HOMEWORK
“EVALUATION OF CONSTRUCTION SITES FOR SEDIMENT CONTROL
COMPLIANCE” HOMEWORK
Use the following 10 words from the reading completed in class and define them without using a
dictionary. In place of using a dictionary, talk with a parent or a non-classroom friend to decide
upon a good definition that explains today’s reading assignment.
1. aggravates
2. residential
3. commercial
4. industrial
5. municipalities
6. mulching
7. velocity
8. stabilization
9. certified
10. marine
342