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Getting Started With Drainage Control :
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Loans: The Party Goes On!
Drainage and erosion are a
natural processes. Do not panic. Every coastal property
has some degree of surface and groundwater flow. You
will never be able to control these drainages entirely.
So the goal of absolute drainage control is usually
not technically feasible nor is it usually necessary.
The practice of drainage control is really the practice
of managing flows to the point where they are not contributing
to accelerated erosion and landsliding along your coastal
slope. Drainage and coastal erosion may be managed but
not eliminated. Therefore, you must plan with them.
Surface and ground
waters influence slope erosion and stability. Each year
wet weather stresses many vulnerable properties to their
points of failure which causes severe erosion and landsliding
events around Puget Sound. These notable occurrences
can usually be traced to the following issues: recent
changes in the surface conditions around a property;
accumulated small slope stability weaknesses that go
undetected or unattended; or poor drainage system performance
on a property.
You have probably
observed some signs of slope distress during a wet weather
season. As a coastal property owner, you should be aware
of the role water plays in the short and long term stability
of coastal slopes. Excessive soil erosion and land movements
can create restoration costs and environmental impacts
costs. Each of these costs is avoidable.
Although this website
deals primarily with managing drainage issues along
coastal slopes, other factors also influence slope stability
and erosion of slopes. These factors include: subsurface
geological characteristics; vegetation management on
and above slopes; property modifications during property
development; and coastal marine processes acting at
the slope toe. Each of these factors should also be
considered in your drainage planning to provide a comprehensive
approach to slope stabilization and erosion control.
Other Ecology publications are available to help with
your planning. Refer to the links section for more information.
The main sections
are introduced on Figure 1. Each section builds on information
presented in previous sections. So, it is important
that you review each section of the website before skipping
directly to specific sections.
Three basic steps
can protect your slope against accelerated erosion and
landsliding.
First,
understand your property. It is not an extensive effort
to generally characterize your slope area and identify
the water movement around the slope.
Second,
identify problems and plan appropriate improvements
into your site. Take the opportunity during property
development to include drainage control with your landscaping
work. On each coastal property, there are typical site
constraints which must be considered. Identifying the
opportunities and constraints of your site are key goals
of your planning effort.
Third,
carefully construct and maintain your drainage system.
Taking the time to ensure that good materials and workmanship
are used on your property cannot be overemphasized.
Give your system periodic maintenance tune-ups.
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