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Water is a frequent topic of conversation these days, with valid concern over the growing scarcity of this resource. In the past few years, however, concerns about too much water have also arisen. From Hurricane Katrina to Superstorm Sandy to our own frightful storm during Halloween last year, unprecedented flooding is emerging as another water-related issue that must be addressed, as our weather patterns become even more unpredictable in the years to come.

In Oregon, too much water is an issue that increasingly should be carefully considered by contractors, developers, and landowners planning their next development or property improvement project. Improper or insufficient drainage of surface water can lead to severe floods and significant property damage, particularly from properties higher in elevation and those that increase impervious surface areas. These types of properties can exacerbate the risk of flooding for properties in lower-lying areas that are in the drainage path. Even when outright flooding is not a concern, excess water from neighboring properties can create new wetlands or just constitute a general nuisance.

While an increase in local flooding will likely bring more stringent regulations on water in the years to come, contractors, developers, and landowners should be attuned to existing laws and regulations, including securing the right permits and approvals for drainage. Property owners should consult an expert or get the right legal advice early in their development projects to ensure that they meet all codes and regulations so that excess water is properly addressed and does not expose the projects to legal liability in the future.

Municipal Drainage Ordinances

Cities in the metropolitan area, including Portland, Lake Oswego, Tigard, and Beaverton, have codes and comprehensive programs to address water. These programs include guidance manuals and technical assistance.

Typically, the drainage standards required by cities are part of a larger stormwater management plan, and are imposed on all development, redevelopment, and improvement projects on private and public property. Municipalities review and permit all regulated projects, and require that stormwater generated from private property—e.g., roofs, private alleys, patios, and driveways—be managed on private property and in privately maintained facilities. A private development may discharge to an existing public facility if it meets certain criteria, and is occasionally allowed to share a stormwater facility with the municipality.

Most programs prefer that stormwater drain into vegetated surface facilities (green infrastructure) to treat and infiltrate the stormwater, to reduce pollution, volume, and peak flow, and to recharge the groundwater.

Most programs also require development projects to have overflow facilities for excess water in the event of a significant storm event. These facilities ensure that if the stormwater facility fails or rainfall exceeds the facility's capacity, the water is routed in a manner that maintains public safety and avoids property damage. Depending on site conditions, this overflow system may include an overflow structure or storage in a parking lot, street, or landscaping area.

Finally, most codes include "drainage reserves" in no-build areas, which ensure that drainage from development does not cause damage or destabilization to an area by ponding, flooding, or other impacts.

Ensuring that a development meets all municipal stormwater control requirements and obtaining a stormwater permit for a development project are early steps that help ensure that a project will not later face unexpected liability.

State Drainage Law

Some properties or projects are located within the jurisdiction of special districts, which are authorized by statute to provide drainage and flood protection. In the metropolitan area, these special districts include the Multnomah County Drainage District No. 1, Peninsula Drainage Districts Nos. 1 and 2, Sandy Drainage Improvement Company, and Sauvie Island Drainage Improvement Company.

These special districts typically have control over all drainage ditches, laterals, drains, canals, sloughs, waterways, and conduits within their boundaries. They operate and maintain drainage systems that could include levees, ditches, and pump stations. Properties that drain into these ditches rely on the drainage systems to expel the water.

A contractor, developer, or landowner looking to ensure that its development does not cause unexpected damages should verify that its project is located within the jurisdiction of a special district and, if so, that it meets special district requirements.

Drainage Common Law

When properties or projects are not within the jurisdiction of a municipality or special drainage district, drainage law is less clear.

In Oregon, an upper-elevation landowner may prudently alter natural flow and collect and accelerate that flow to a lower-elevation property. But an upper-elevation landowner cannot:

  • Collect and concentrate the water before discharge onto a lower-elevation property;
  • Discharge at a place where the water would otherwise not naturally flow; or
  • Increase the natural flow of a watercourse to the detriment of a lower-elevation user.

Lower elevation landowners may be liable to the higher-elevation landowner for altering or blocking the course of ordinary flows in a manner that forces the water back uphill.

Given the specific analysis required for each unique project location, determining whether downhill drainage is permissible can be as unpredictable as future weather events. Contractors, developers, and landowners should work with legal and other technical experts to ensure that their next development or improvement project will not imprudently inundate a lower-elevation property. When it is feasible, a landowner should obtain all necessary government approvals, even if they come from an entity with no specific authority over drainage or stormwater management. Another option is to secure the right to drain across another's property through an express easement, clarifying each neighbor's rights.

So, while weather patterns are becoming more unpredictable and concerns over too much water are not going away, thoughtful future planning of a project to deal with these problems will be key. Luckily, contractors, developers, and landowners have tools and access to experts today to help them manage these risks.

A version of this article appeared in the March 21, 2016 issue of the Daily Journal of Commerce.

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