Authorizing local government unit or watershed management organization property tax levies within subwatershed units to pay the increased costs of preparing water management plans, requiring certification of the levies to the county auditor; increasing the levy limit for watershed district administrative funds and changing the name of the funds to general funds; authorizing watershed district ad valorem property tax levies for the increased costs of revising or amending water management plans and for certain nondrainage projects necessary to implement district purposes (mk)