North Carolina long adhered to the Civil Law Rule in regard to surface water drainage. This rule obligates owners of lower land to receive the natural flow of surface water from higher lands. It subjects a landowner to liability whenever he interferes with the natural flow of surface waters to the detriment of another in the use and enjoyment of his land. Since almost any use of land involves some change in drainage and water flow, a strict application of the civil law principles was impracticable in a developing society. Thus, a more moderate application of this rule to allow a landowner reasonable use of his property evolved.

The North Carolina Supreme Court formally adopted the Rule of Reasonable Use with respect to surface water drainage and abandoned the Civil Law Rule (Pendergrast V. Aiken) in August 1977. The adopted Reasonable Use Rule allows each landowner to make reasonable use of his land even though by doing so, he alters in some way the flow of surface water thereby harming other landowners, liability being incurred only when this harmful interference is found to be unreasonable and causes substantial damage.

There are still some unanswered questions in the application of the adopted Reasonable Use Rule to specific areas of State agency activities. However, the rule is in line with the realities of modern life and will provide just, fair and consistent treatment. Therefore, the policies and practices of the Division of Highways in regard to surface drainage matters follow this rule.

The Reasonable Use Rule places responsibility on the "landowner" to make reasonable use of his land. While "reasonable use" is open for interpretation on a case by case basis, it would certainly infer from an engineering standpoint that provisions for, and treatments of, surface waters on the property are made in accordance with sound, reasonable and acceptable engineering practices. Therefore, the Engineer must see that these principals are reflected in the design process.

The rule also states that liability incurs only when harmful interference with the surface water is found to be unreasonable and causes substantial damage. Therefore, it is incumbent on the Engineer to evaluate the potential effects of surface water activities on both up and downstream properties and to include provision in the design to hold these effects to reasonable levels.

These types of engineering practices, considerations and their proper documentation are contained in these Highway Drainage Guidelines, as well as in other referenced materials.

The following are general drainage policies and practices of the North Carolina Division of Highways involving both design and maintenance activities.

Development of property can cause an increase in the quantity and peak rate of flow by increasing impervious areas and providing more hydraulically efficient channels and overland flow. It is the policy of the Division of Highways to develop and make reason- able use of its lands and rights-of-way through sound, reasonable and acceptable engineering practices and to deny responsibility for augmented or accelerated flow caused by its improvements unless determined to cause unreasonable and substantial damages. It is likewise the policy of the Division of Highways to expect this same practice and acceptance of responsibility by other property owners and those engaged in the development of these properties.

Diversions are defined as the act of altering the path of surface waters from one drainage outlet to another. It is the policy of the Division of Highways to design and maintain its road systems, so that no diversions are created thereby, insofar as is practicable from good engineering practice.

Any person(s) desiring to create a diversion into any highway rights-of-way shall do so only after receiving written permission. This permission will be granted only after it has been determined that the additional flow can be properly handled without damage to the highway, that the cost for any required adjustments to the highway system will be borne by the requester, and that appropriate consideration and measures have been taken to indemnify and save harmless the Division of Highways from potential downstream damage claims. It is Division of Highways policy not to become a party to diversions unless refusal would create a considerable and real hardship to the requesting party.

Drainage structures and ditches shall be kept open and maintained at a functioning level such that they do not present an unreasonable level of damage potential for the highway or adjacent properties.

Where the elevation of the flow-line of an existing culvert under a highway is not low enough to adequately provide for natural drainage, the Division of Highways will assume full responsibility for lowering the culvert or otherwise provide needed improvement.

Where a requested culvert invert adjustment is a result of a property owner lowering the flow-line of the inlet and outlet ditch in order to improve drainage of his property, the following considerations shall be given to the action taken:

• The lowered drain must have a reasonable expectancy of being functional and maintainable.
• Division of Highways participation (up to full cost) must be based on benefit gained by the roadway drainage system as a result of the lowering.
• Where the new installation is of doubtful, or no benefit to highway drainage, the requesting party must bear the entire cost of installation.

Where the size of an existing highway culvert is determined to be of unacceptable adequacy in regard to the roadway system functioning as a result of a general overall development of the watershed, it is the Division of Highways' responsibility to replace the structure or otherwise take appropriate action.

Where this same culvert inadequacy is the result of a single action or development, it is felt to fall within the realm of "unreasonable and substantially damaging" under the State adopted drainage ruling. Therefore, the party responsible for the action or development should bear the cost of replacement.

Where a new culvert crossing is requested, if the culvert is required for proper highway drainage or sufficient benefits to the highway drainage system would occur, the full cost will be borne by the Division of Highways providing there is no diversion of flow involved. Where the new installation is of doubtful or no benefit to highway drainage, the property owner will bear the entire cost. When both parties receive benefit, a joint effort may be negotiated.

Established culvert crossings will be maintained and requests to eliminate any culvert should have the approval of the State Hydraulics Engineer.

When new private drives are constructed entering the highway, the property owner can furnish, delivered to the site, the amount, type and size pipe designated by the Division of Highways, to be installed by maintenance forces.

No alteration, attachment, extension, nor addition of appurtenance to any culvert shall be allowed on highway rights-of- way without written permission.

While it is the responsibility of the Division of Highways to provide for adequate drainage for constructing and maintaining the State Highway System, it is not its policy nor responsibility to provide improved drainage for the general area traversed by such roads, unless incidental to the drainage of the road or highway itself. Drainage involvement outside the highway rights-of-way is limited to two general areas of justification:

• Sufficient benefit could be gained by such action to warrant the cost. These benefits would be in such areas as reduction in roadway flood frequency or extent, facilitation of maintenance, or a reduction in potential damages.

• Work is required to correct a problem or condition created by some action of the Division of Highways.

It is not the responsibility of the Division of Highways to eliminate flooding on private property that is not attributable to acts of the agency or its representative.

In general, outlet ditches will be maintained for a sufficient distance below the road to provide adequate drainage therefore. On large outlets serving considerable areas outside the right-of-way, the maintenance should be done on a cooperative basis, with the benefited properties bearing their proportionate share. Shares will, in general, be based on proportioning of runoff from the areas served by the outlet.

It is not the policy of the Division of Highways to pipe inlet or outlet drains, natural or artificial, outside the right- of-way, which existed as open drains prior to existence of the highway. Where the property owner wishes to enclose an inlet or outlet, the Division of Highways may install the pipe adjacent to the right-of-way if justified by reason of reduced maintenance, safety or aesthetics if the pipe is furnished at the site by the property owner. This does not apply to the development of commercial property.

It is the policy of the Division of Highways that when a drain is blocked below the highway, which is detrimental to highway drainage, if from natural causes, the Division of Highways will take necessary measures to remove the block or obstruction. Where the block is caused by wrongful acts of others, it is the policy of the Division of Highways to take whatever recourse deemed advisable and necessary to cause the party responsible to remove the block. Where a block occurs downstream of a highway, whether natural or artificial, and is of no consequence to the Division of Highways, it is the policy to remain neutral in causing its removal.

State Statute (G. S. 136-92) provides that anyone obstructing any drains along or leading from any public road is guilty of a misdemeanor.

Drainage Easements

Where runoff is discharged from the right of way at a point where there is no natural drain or existing ditch, a permanent drainage easement is required to allow construction of a ditch or channel to convey the discharge to an acceptable natural outlet. When the discharge is into a natural drain or existing ditch and the increase in flow would exceed the capacity or otherwise create a problem, a temporary drainage easement can be obtained to allow enlarging or otherwise improving the drain to a point where the increase discharge will not cause damage.

It is generally preferable that any structural feature such as a drop inlet, catch basin, or pipe-end be contained within a permanent easement.

When roads and streets built by others are accepted onto the state system for maintenance, responsibility for the drainage system, discharge pattern and outlet locations is as it exist at the time of acceptance and is limited to the rights-of-way.

Information on design, review and approval requirements is provided in the reference (3),"Subdivision Roads- Minimum Construction Standards"