Section 2: Current Water Conditions

Water Quality Conditions

In the WQIP, Responsible Agencies (RAs) identified Priority Water Quality Conditions (PWQCs) by evaluating receiving water conditions, MS4 discharges and their potential impacts, and potential sources of pollutants in the WMA. The WQIP also details the process the RAs used to identify the Highest Priority Water Quality Conditions (HPWQCs). Tables 2 and 3 list the HA-specific PWQCs and HPWQCs, respectively, per the 2021 WQIP.

Table 2: Carlsbad WMA WQIP Priority Water Quality Conditions (from 2021 WQIP)

Hydrologic Area	Applicable Receiving Water	PWQC (pollutant or stressor)	Temporal Extent
All	All within WMA	Trash	Dry and Wet Weather
All	All within WMA	Riparian Habitat Degradation	Dry and Wet Weather
Loma Alta	Loma Alta Slough	Eutrophic conditions	Dry Weather (Between May and October)
Loma Alta	Loma Alta Slough	Indicator Bacteria	Dry and Wet Weather
Loma Alta	Loma Alta Creek	Toxicity	Dry Weather
Loma Alta	Pacific Ocean Shoreline at Loma Alta Creek Mouth	Indicator Bacteria	Dry and Wet Weather
Buena Vista Creek	Buena Vista Lagoon	Indicator Bacteria	Dry and Wet Weather
Buena Vista Creek	Buena Vista Lagoon	Sediment/Siltation	Dry and Wet Weather
Buena Vista Creek	Buena Vista Lagoon	Nutrients	Dry Weather
Agua Hedionda	Agua Hedionda Creek	Indicator Bacteria	Dry and Wet Weather
Agua Hedionda	Agua Hedionda Creek	Toxicity	Dry and Wet Weather
Agua Hedionda	Agua Hedionda Creek	Nutrients	Dry and Wet Weather
Agua Hedionda	Agua Hedionda Creek	Sediment – Erosion - Hydromodification	Wet Weather
Agua Hedionda	Agua Hedionda Lagoon (SHELL)	Fecal Indicator Bacteria	Wet Weather
Agua Hedionda	Agua Hedionda Lagoon (REC-1)	Enterococcus	Dry and Wet Weather
Buena Creek	Buena Creek	Nitrate and Nitrite	Dry Weather
San Marcos	Lower – Pacific Ocean Shoreline at Moonlight Beach	Indicator Bacteria	Dry and Wet Weather
San Marcos	Lower – San Marcos Creek	Eutrophic (nutrients)	Dry Weather
Encinitas Creek	Encinitas Creek	Toxicity	Dry Weather
Upper San Marcos Creek	Upper San Marcos Creek	Nutrients	Dry and Wet Weather
Upper San Marcos Creek	Upper San Marcos Creek below Via Vera Cruz	Indicator Bacteria	Dry and Wet Weather
San Marcos Lake	San Marcos Lake	Nutrients	Dry and Wet Weather
Escondido Creek	Escondido Creek	Indicator Bacteria	Dry and Wet Weather
Escondido Creek	Escondido Creek	Toxicity	Dry Weather
Escondido Creek	Escondido Creek	Nutrients	Dry and Wet Weather
San Elijo Lagoon	San Elijo Lagoon	Indicator Bacteria	Dry and Wet Weather
San Elijo Lagoon	San Elijo Lagoon	Sediment/Siltation	Dry and Wet Weather

Notes:

1. All within WMA indicates conditions that apply to multiple or all Hydrologic Areas within the WMA.
2. Nutrients category includes at least two or more of the following pollutants: Dissolved phosphorus, Orthophosphate, Total phosphorus, Total Kjeldahl Nitrogen, Total Nitrogen, Eutrophication, or Benthic Algae.
3. SHELL data were collected by CDPH for the protection of public health related to commercial shellfish harvesting in the Lagoon. CDPH water quality benchmarks are established by the National Shellfish Sanitation Program and exist for fecal coliform only.
4. REC-1 evaluation involves data for enterococcus only in saline waters (e.g., lagoons, ocean) due to the Bacteria Provisions adopted by the State Water Resources Control Board.
5. San Marcos Lake is privately owned by the Citizens Development Corporation.

This table provides a comprehensive breakdown of the priority water quality conditions identified for each hydrologic area within the Carlsbad WMA as per the latest WQIP update.

Note: The use herein of the terms "pollutant(s)" and "pollution" should not be construed as an admission by the Responsible Agencies that the substances referenced herein constitute "pollutants" as that term is used in the context of liability insurance "pollution" exclusions as construed by California insurance law.

Table 3: Carlsbad WMA WQIP Highest Priority Water Quality Conditions

Hydrologic Area	Applicable Receiving Water	HPWQC (pollutant or stressor)	Temporal Extent
Loma Alta	Loma Alta Slough	Eutrophic (nutrients)	May-Oct
Buena Vista Creek	Buena Vista Lagoon	No HPWQC	NA
Agua Hedionda	Agua Hedionda Creek	Riparian Habitat Degradation	Wet and Dry Weather
Agua Hedionda	Agua Hedionda Creek	Hydromodification Impacts	Wet and Dry Weather
Encinas	Pacific Ocean	No HPWQC	NA
San Marcos	Lower – Pacific Ocean Shoreline at Moonlight Beach	Impairment of REC-1 (Indicator Bacteria)	Wet and Dry Weather
San Marcos	Upper – San Marcos Creek	Eutrophic (nutrients)	Wet and Dry Weather
Escondido Creek	Escondido Creek	Riparian Habitat Degradation	Wet and Dry Weather

Numeric goals and schedules were established for each HPWQC, and strategy implementation is intended to achieve the identified goals. Specific information on the goals, schedules, and progress for each HA is included in Section 3 of this annual report.

HPWQC = Highest Priority Water Quality Condition; NA = Not Applicable; REC-1 = water contact recreation beneficial use

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