Know your data sources.

Louisiana DEQ water-quality datasets. AGOL Feature Services, no auth. - search303dImpairedWaters ⭐ — IR2020 subsegments where a designated use is Not Supported (303(d)) - searchSubsegmentsByUse ⭐ — same layer, any use-rating - searchWatershedBasins (12), searchAmbientMonitoringSites (~761 LEAU active), searchFishAdvisories (62) - getServiceInfo quirks: subsegments + flowlines have NO parish — use BASIN (12 names: ATCHAFALAYA / CALCASIEU / ...) or bbox. Use codes: PCR/SCR/FWP/DWS/ONR/OYS/AGR/LAL. Status: Fully Supported / Not Supported / Insufficient Data / Not a Use / No Data Collected. Fish Advisories' Parishes is free-text ("Calcasieu and Cameron"); LIKE-matched. Air emissions + hazardous waste are NOT published as LDEQ Feature Services.

North Dakota DEQ environmental data. ND DEQ AGOL + FracTracker mirror; no auth. - searchSpills (~5.4K) ⭐ Bakken oil + brine spills (FracTracker mirror, static Dec 2013-Jul 2019) - searchStormwaterPermits (~2.9K) ⭐ Bakken well-pad construction permits by operator - searchGroundwaterMonitoring (~278), searchImpairedStreams (~34.8K Cat 5 = 303d), getServiceInfo upstream quirks: ND DEQ does NOT publish spills/USTs/air permits/abandoned pits as Feature Services — methods reframed against actual surface + FracTracker spills. Stormwater, groundwater, impaired-stream layers have NO COUNTY column (county errors; use bbox/near). Oil + brine spill services are one dataset; spillType comes from reported volumes; operator matches Well_Name.