Indiana Code Title 36. Local Government § 36-9-27-68

(1) Prepare and make available to the public design standards of rainfall intensity and frequency for urban land, design standards of storm water runoff for urban land, or both.  In preparing these standards, the county surveyor shall consider official weather bureau information, design criteria of the Indiana department of natural resources, the published recommendations of the United States bureau of public roads, and all available local, topographical, geological, and statistical information that may affect the design standard of runoff from urban land.  The county surveyor may give special consideration to those weather events in which rainfall occurs under conditions when soil tends to be impervious due to frost or other natural causes.

(2) Prepare hydraulic calculations for the channel design of the urban drain, taking into consideration hydraulic gradients, friction factors, dimensions, and other engineering variables.

(3) Design the channel or dam required for the urban drain, including any necessary rerouting and taking into consideration the structures and structural characteristics of the soil.

(4) Furnish design information for all new drainage structures (including local flood control dikes) that may be needed to properly drain urban land or impound water in a small lake in the most efficient and economical manner.

(5) Keep available maps, listings, or other information showing current land use and projections of future land use in the area affected by the urban drain.  In preparing this information, the county surveyor shall consider recommendations of state and local planning agencies, plan commissions, zoning boards, and similar bodies.

(6) Include in the county surveyor's report to the board on the construction or reconstruction of an urban drain the county surveyor's recommended designation of each parcel of affected land in the watershed of the urban drain as either urban land or rural land.