Modifications necessary to preserve the structural integrity of existing non-Federal projects may be constructed at additional Federal and non-Federal expense in conjunction with approved rehabilitation work. The additional Federal cost will be limited to not more than one-third of the estimated Federal construction cost of rehabilitation to preflood level of protection, or $100,000, whichever is less. The modification work must be economically justified. Non-Federal interests are required to contribute a minimum of 25% of the total construction costs of the modification, LERRD's, and any additional funds necessary to support the remaining cost of the modification beyond what the Corps can provide. Engineering and design costs will be at Corps cost.

(a) Cash contributions. Non-Federal contributions will be only in cash. In-kind services are not permitted for modification work.

(b) Protection of additional areas. Modifications designed to provide protection to additional area are not authorized.