Water Supply LawUse and ownership of water (≈ Water Law).•Riparian Doctrine – land owners have a right to use water adjacent to their land (but they cannot significantly affect flow to other holders of rights). “Common Law Rule of the humid states”State level, set by precedent. Eastern U.S.•Prior Appropriation – “First in time is first in right.” 1stto use for a beneficial use has the right to continue use over subsequent claims. “Colorado doctrine”State level, set by precedent. Western U.S.Colorado Water Supply LawBeneficial use includes agriculture, industry, and household use. Not wildlife or recreational uses.•Colorado Water Conservation Board –State Entity set up via state legislation to obtain water rights for maintaining in-stream flow. (Late development means rights are junior.)This effectively provides a means for maintaining stream flow and lake level for recreational and conservation purposes.•Previously wells were viewed as unconnected to surface waters. •Water rustling is common. Water Quality LawMaintenance of water quality standards (≈ Environmental Law emphasizing water).•Point-source (PS) pollution – A pollutant enters water from a single “point.”•Non-point-source (NPS) pollution – A pollutant enters water from surface runoff.•Clean Water Act (1972) – enacted means for ensuring minimum water quality standards.1969 – Cuyahoga River in Cleveland caught on fire. It was the last of 13 Cuyahoga River fires. The largest was in 1952. The 1969 fire was covered extensively by Time magazine.Clean Water Act•EPA & States administer – Water Quality Standards, Point Source Emissions, and Enforcement•Army Corps of Engineers administer –dredging/fill material and navigable waterregulation and permitting; can issue blanket permits. (Irrigation maintenance always exempt.)•Not Regulated or ExemptFarm runoff (NPS – fertilizers, herbicides, and pesticides)Oil and natural gas runoff (Exempt from CWA since 2005)•Critical Resource Waters designated for additional protection.Politics  LegislationLaw: Federal, State, & LocalRegulators IdentifiedRegulations Enacted Based on