{
  "claims": [
    {
      "claim": {
        "claim_id": "claim-del-valle-boat-inspection",
        "evidence_ids": [
          "evidence-del-valle-boat-inspection",
          "evidence-del-valle-ebrpd-boat-inspection",
          "evidence-ebrpd-mussels-del-valle-inspection"
        ],
        "predicate": "boat_inspection_required",
        "spatial_scope_ids": [
          "scope-lake-del-valle"
        ],
        "subject_id": "lake-del-valle",
        "temporal_scope": null,
        "value": true
      },
      "evidence": [
        {
          "claim_id": "claim-del-valle-boat-inspection",
          "evidence_id": "evidence-del-valle-boat-inspection",
          "notes": "",
          "observation_id": "observation-del-valle-boating-swimming",
          "stance": "supports"
        },
        {
          "claim_id": "claim-del-valle-boat-inspection",
          "evidence_id": "evidence-del-valle-ebrpd-boat-inspection",
          "notes": "",
          "observation_id": "observation-del-valle-ebrpd-golden-mussel",
          "stance": "supports"
        },
        {
          "claim_id": "claim-del-valle-boat-inspection",
          "evidence_id": "evidence-ebrpd-mussels-del-valle-inspection",
          "notes": "",
          "observation_id": "observation-ebrpd-mussels-program-scope",
          "stance": "supports"
        }
      ],
      "observations": [
        {
          "artifact_refs": [],
          "content": "The page lists two swimming beaches, lifeguards during posted periods, boat rentals, and a public launch for boats of any size; it warns that boaters must comply with the Invasive Mussel Prevention Program and mandatory inspections.",
          "observation_id": "observation-del-valle-boating-swimming",
          "observed_at": null,
          "observer": "user-supplied page transcription",
          "retrieved_at": "2026-09-20T00:00:00+00:00",
          "source_id": "source-reserveamerica-del-valle-overview-110003"
        },
        {
          "artifact_refs": [],
          "content": "At retrieval, the page stated that a boat launched at Contra Loma would be quarantined for 30 days from inspected lakes including Del Valle; vessels must be cleaned, drained, and dried, and boat bands are honored only by the lake that issued them. It also requires campground guests with watercraft to complete inspection before campground check-in.",
          "observation_id": "observation-del-valle-ebrpd-golden-mussel",
          "observed_at": "2026-09-20T00:00:00+00:00",
          "observer": "user-supplied page transcription",
          "retrieved_at": "2026-09-20T00:00:00+00:00",
          "source_id": "source-ebrpd-del-valle-park-page"
        },
        {
          "artifact_refs": [],
          "content": "EBRPD requires watercraft inspection at Contra Loma, Del Valle, Lake Chabot, Quarry Lakes, and Shadow Cliffs. Covered craft include boats, kayaks, canoes, sailboats, inflatable craft, and every form of floating board. Campers with watercraft must complete inspection before campground check-in.",
          "observation_id": "observation-ebrpd-mussels-program-scope",
          "observed_at": null,
          "observer": "user-supplied page transcription",
          "retrieved_at": "2026-09-20T00:00:00+00:00",
          "source_id": "source-ebrpd-invasive-mussel-program"
        }
      ],
      "sources": [
        {
          "locator": "https://www.reserveamerica.com/explore/del-valle/EB/110003/overview",
          "publisher": "ReserveAmerica / East Bay Regional Park District",
          "source_id": "source-reserveamerica-del-valle-overview-110003"
        },
        {
          "locator": "https://www.ebparks.org/parks/del-valle",
          "publisher": "East Bay Regional Park District",
          "source_id": "source-ebrpd-del-valle-park-page"
        },
        {
          "locator": "https://www.ebparks.org/recreation/boating/invasive-mussels",
          "publisher": "East Bay Regional Park District",
          "source_id": "source-ebrpd-invasive-mussel-program"
        }
      ]
    },
    {
      "claim": {
        "claim_id": "claim-del-valle-swimming",
        "evidence_ids": [
          "evidence-del-valle-swimming"
        ],
        "predicate": "published_swimming_facilities",
        "spatial_scope_ids": [
          "scope-lake-del-valle"
        ],
        "subject_id": "lake-del-valle",
        "temporal_scope": null,
        "value": {
          "beaches": 2,
          "lifeguards": "during posted periods"
        }
      },
      "evidence": [
        {
          "claim_id": "claim-del-valle-swimming",
          "evidence_id": "evidence-del-valle-swimming",
          "notes": "",
          "observation_id": "observation-del-valle-boating-swimming",
          "stance": "supports"
        }
      ],
      "observations": [
        {
          "artifact_refs": [],
          "content": "The page lists two swimming beaches, lifeguards during posted periods, boat rentals, and a public launch for boats of any size; it warns that boaters must comply with the Invasive Mussel Prevention Program and mandatory inspections.",
          "observation_id": "observation-del-valle-boating-swimming",
          "observed_at": null,
          "observer": "user-supplied page transcription",
          "retrieved_at": "2026-09-20T00:00:00+00:00",
          "source_id": "source-reserveamerica-del-valle-overview-110003"
        }
      ],
      "sources": [
        {
          "locator": "https://www.reserveamerica.com/explore/del-valle/EB/110003/overview",
          "publisher": "ReserveAmerica / East Bay Regional Park District",
          "source_id": "source-reserveamerica-del-valle-overview-110003"
        }
      ]
    }
  ],
  "entities": [
    {
      "entity_id": "lake-del-valle",
      "kind": "lake",
      "name": "Lake Del Valle"
    }
  ],
  "history": [
    {
      "action": "ADD",
      "change_set_id": "wp-20260920-del-valle-reserveamerica-foundation",
      "evidence_refs": [],
      "knowledge_gap_refs": [],
      "path": "canonical/v0/observations/observation-del-valle-boating-swimming.json",
      "reason": "Establish the source-backed Del Valle foundation from the supplied ReserveAmerica overview.",
      "record_id": "observation-del-valle-boating-swimming",
      "record_type": "observation",
      "summary": "Establish Del Valle park and family-campground knowledge from the ReserveAmerica overview while preserving inventory, permit, and operational-condition uncertainty."
    }
  ],
  "navigation": {
    "next_id": "observation-del-valle-cabin-faq-amenities",
    "position": 4,
    "previous_id": "observation-del-valle-backpacking-reservation",
    "total": 1318
  },
  "observations": [
    {
      "artifact_refs": [],
      "content": "The page lists two swimming beaches, lifeguards during posted periods, boat rentals, and a public launch for boats of any size; it warns that boaters must comply with the Invasive Mussel Prevention Program and mandatory inspections.",
      "observation_id": "observation-del-valle-boating-swimming",
      "observed_at": null,
      "observer": "user-supplied page transcription",
      "retrieved_at": "2026-09-20T00:00:00+00:00",
      "source_id": "source-reserveamerica-del-valle-overview-110003"
    }
  ],
  "record": {
    "artifact_refs": [],
    "content": "The page lists two swimming beaches, lifeguards during posted periods, boat rentals, and a public launch for boats of any size; it warns that boaters must comply with the Invasive Mussel Prevention Program and mandatory inspections.",
    "observation_id": "observation-del-valle-boating-swimming",
    "observed_at": null,
    "observer": "user-supplied page transcription",
    "retrieved_at": "2026-09-20T00:00:00+00:00",
    "source_id": "source-reserveamerica-del-valle-overview-110003"
  },
  "record_type": "observation",
  "related_records": [],
  "sources": [
    {
      "locator": "https://www.reserveamerica.com/explore/del-valle/EB/110003/overview",
      "publisher": "ReserveAmerica / East Bay Regional Park District",
      "source_id": "source-reserveamerica-del-valle-overview-110003"
    }
  ]
}