(a) In the case of subdivisions, the owner shall dedicate and the city accept the land or any interest in land necessary for the drainage facilities that are constructed to city standards and that are to be maintained and repaired (and operated as the case may be) by the city pursuant to HRS § 265A-1, by way of easements or in fee simple as determined by the chief engineer. The land document for stream improvements shall include the following covenant:
That the grantor shall include in all conveyances of its land in the vicinity of the stream improvement area a statement that the drainage structure was designed and constructed by the grantor or the grantor’s authorized agent or developer to at least meet the minimum criteria set forth in the storm drainage standards of the city, dated _____________, but that the city does not guarantee that the drainage structure is adequate to confine all flood waters to the stream improvement area.
(b) In the case of subdivisions, drainage facilities that only serve private properties shall have easements in favor of the affected property owners. This includes interceptor ditches.
(c) Before the subdivision of any land is approved by the chief engineer, the chief engineer shall check the subdivision plans against the areas of possible inundation in the watershed area as shown shaded on the maps incorporated by reference in § 43-11.3. Such possible inundated areas are to be designated “possible flood areas.” No subdivision shall be approved by the chief engineer, unless all lots in a subdivision that are wholly or partially within the “possible flood area” designation have been subjected to the following encumbrance and noted as a legend on the subdivision map to the effect that:
This lot (Lots _____________) is(are) in a “possible flood area.” All existing drainage structures have been designed and have been or are being constructed to at least meet the minimum criteria set forth in the storm drainage standards of the city; however, the city does not guarantee that the drainage structures will confine all flood waters to the drainage facilities at all times.
(d) The developer shall pay the entire cost of the drainage facilities to satisfy the anticipated drainage requirements of all surface water that may flow through or over the proposed subdivision.
(e) Where city standards require drainage facilities of greater capacity than necessary to serve the land being subdivided or developed, to dispose of water diverted or concentrated by the city into such drainage system, the city may pay the difference in costs of materials and excavation, if any. The cost of materials to the city shall be based on the costs of the materials delivered at the site. Upon a determination by the chief engineer that such larger facilities are required, and if HRS Chapter 103, or any amendatory act thereto, are applicable, the property owner shall deposit with the city an amount equal to the cost of construction of the drainage facilities allocable to the property owner’s land, based upon current city cost data for comparable installations, but the amount paid by the property owner shall be adjusted, if necessary, on the basis of final costs.
(f) The chief engineer may require the construction of permanent detention or retention drainage structures or other engineering control facilities to contain or divert stormwater runoff to satisfy the anticipated drainage requirement of all surface waters that may flow through or over the proposed subdivision, or to meet any conditions of the city NPDES permit. When required, such facilities will be constructed to provide gravity settling of sediments, suspended solids, and other particulate pollutants.
(g) The chief engineer shall, pursuant to federal requirements, establish controls on the timing and rate of discharge of stormwater runoff from any new development or redevelopment as may be appropriate to reduce stormwater runoff pollution to the maximum extent practicable through the implementation of best management practices (BMPs) and engineering control facilities, designed to reduce the generation of pollutants. This may, where feasible and pursuant to city standards, include limiting peak stormwater runoff rates for storms of higher frequencies to predevelopment levels.
(Sec. 16-6.9, R.O. 1978 (1983 Ed.)) (1990 Code, Ch. 14, Art. 12, § 14-12.9) (Am. Ords. 92-122, 96-34)