For the purposes of this chapter , unless the context otherwise requires: 1. “Council” means the water resources coordinating council created in section 466B.3 . 2. “Iowa nutrient reduction strategy” means the same as defined in section 455B.171 . 3. “Political subdivision” means any of the following: a. A city. b. A county. c. A soil and water conservation district described in section 161A.5 . d. A benefited recreational lake district or a water quality district or a combined district incorporated as a public entity and organized pursuant to chapter 357E . e. A rural improvement zone established pursuant to chapter 357H . 4. “Regional watershed” means a watershed of hydrologic unit code scale 8. 5. “Subwatershed” means a watershed of hydrologic unit code scale 12 or smaller. 6. “Watershed” means a geographic area in which surface water is drained by rivers, streams, or other bodies of water. 2008 Acts, ch 1034, §2 ; 2013 Acts, ch 132, §57 ; 2016 Acts, ch 1020, §1 ; 2018 Acts, ch 1152, §9, 10 ; 2020 Acts, ch 1063, §250