Los Angeles region water board briefs panel: nurseries dominate local irrigated agriculture; reporting rules pose unique challenges

Los Angeles Regional Water Quality Control Board (Region 4) staff outlined how irrigated agriculture in the Los Angeles region differs from the Central Valley and Central Coast and told the expert panel that statewide one‑size‑fits‑all approaches will create implementation problems without regional flexibility.

Key points from the regional presentation - Geography and scale: Ventura County accounts for roughly 98% of the region’s irrigated agriculture. Los Angeles County’s agricultural acreage is small and highly fragmented, with many small, diversified operations (some as small as 0.1–1.3 acres reported). Ventura’s irrigated acreage clusters on the coastal plain and rivers and includes berries, nursery stock, avocados and citrus. - Nursery reporting challenges: growers often produce containerized plants rather than harvested in‑ground crops. Staff said there are no accepted crop coefficients for nursery stock and that fertilizer is commonly applied to pots (slow release); sales records often do not quantify number or size of plants in a way that maps directly to nitrogen removal metrics. - Lease and easement farms: many operations sit in utility easements or are leased and can be transient; this complicates long‑term multiyear tracking required for trend analysis. - Limited regional A–R data to date: Region 4’s first deadline for reporting A–R under the East San Joaquin/Statewide requirements is March 2026, leaving the region underrepresented in statewide A–R datasets. - Surface water vs groundwater: Region 4 staff said they observe surface‑water impairments in parts of Ventura County and are pursuing TMDL compliance paths, but that groundwater nitrate trends are limited in their dataset: only a few wells exceed 10 mg/L nitrate‑N and only a handful showed increasing trends.

Why it matters: Panelists heard that policy recommendations must consider regional differences in crops, irrigation, land tenure and data availability. Staff urged the panel to avoid statewide mandates that fail to accommodate small, highly diversified, urban‑edge agricultural operations.

Ending: Region 4 requested recommendations that (1) allow local flexibility, (2) account for nursery and nontraditional operations when designing A–R rules and (3) avoid unintended burdens on small and non‑English‑speaking growers.