Stormwater management and erosion and sediment control; agreement in lieu of plan; farm buildings and agritourism activities; small construction activity. Includes farm buildings, any building or structure used for agritourism activity, and any related impervious surface, including roads, driveways, and parking areas, in the respective definitions of an agreement in lieu of a plan in the stormwater management and erosion and sediment control laws. Current laws define an agreement in lieu of a plan to cover only single-family residences. The bill also requires the State Water Control Board to establish by regulation a procedure by which a registration statement shall not be required for coverage under the General Permit for Discharges of Stormwater from Construction Activities for a small construction activity, defined in the bill, involving a single-family detached residential structure. This bill is identical to HB 1848.