{
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        "evidence_ids": [
          "evidence-del-valle-ebrpd-east-beach-algae",
          "evidence-ebrpd-algae-east-beach-caution",
          "evidence-ebrpd-swimming-east-caution",
          "evidence-ebrpd-water-quality-east-caution"
        ],
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          "scope-del-valle-east-beach"
        ],
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          "starts_on": "2026-09-20"
        },
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      },
      "evidence": [
        {
          "claim_id": "claim-del-valle-ebrpd-east-beach-algae",
          "evidence_id": "evidence-del-valle-ebrpd-east-beach-algae",
          "notes": "",
          "observation_id": "observation-del-valle-ebrpd-water-quality",
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        },
        {
          "claim_id": "claim-del-valle-ebrpd-east-beach-algae",
          "evidence_id": "evidence-ebrpd-algae-east-beach-caution",
          "notes": "",
          "observation_id": "observation-ebrpd-algae-current-del-valle",
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        },
        {
          "claim_id": "claim-del-valle-ebrpd-east-beach-algae",
          "evidence_id": "evidence-ebrpd-swimming-east-caution",
          "notes": "",
          "observation_id": "observation-ebrpd-swimming-current-beaches",
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        },
        {
          "claim_id": "claim-del-valle-ebrpd-east-beach-algae",
          "evidence_id": "evidence-ebrpd-water-quality-east-caution",
          "notes": "",
          "observation_id": "observation-ebrpd-water-quality-current-del-valle",
          "stance": "supports"
        }
      ],
      "observations": [
        {
          "artifact_refs": [],
          "content": "At retrieval, the EBRPD page posted a blue-green algae Caution Advisory for the East Swim Beach and stated that the West Swim Beach had no water because of low lake levels.",
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        },
        {
          "artifact_refs": [],
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          "observation_id": "observation-ebrpd-algae-current-del-valle",
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          "source_id": "source-ebrpd-blue-green-algae"
        },
        {
          "artifact_refs": [],
          "content": "At retrieval, East Beach had a blue-green algae Caution Advisory and West Beach had no water because of low lake levels.",
          "observation_id": "observation-ebrpd-swimming-current-beaches",
          "observed_at": "2026-09-20T00:00:00+00:00",
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          "source_id": "source-ebrpd-del-valle-swimming"
        },
        {
          "artifact_refs": [],
          "content": "At retrieval, the table listed a Caution algae advisory at Del Valle East Beach and no advisory at West Beach, where there was no water because of low lake levels.",
          "observation_id": "observation-ebrpd-water-quality-current-del-valle",
          "observed_at": "2026-09-20T00:00:00+00:00",
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        {
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          "source_id": "source-ebrpd-del-valle-park-page"
        },
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          "publisher": "East Bay Regional Park District",
          "source_id": "source-ebrpd-blue-green-algae"
        },
        {
          "locator": "https://www.ebparks.org/recreation/swimming/del-valle",
          "publisher": "East Bay Regional Park District",
          "source_id": "source-ebrpd-del-valle-swimming"
        },
        {
          "locator": "https://www.ebparks.org/natural-resources/water-quality",
          "publisher": "East Bay Regional Park District",
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        }
      ]
    },
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        },
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          "evidence_id": "evidence-del-valle-ebrpd-west-beach-water",
          "notes": "",
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        },
        {
          "claim_id": "claim-del-valle-ebrpd-west-beach-water",
          "evidence_id": "evidence-ebrpd-algae-west-beach-no-water",
          "notes": "",
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        },
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          "claim_id": "claim-del-valle-ebrpd-west-beach-water",
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        },
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          "claim_id": "claim-del-valle-ebrpd-west-beach-water",
          "evidence_id": "evidence-ebrpd-water-quality-west-no-water",
          "notes": "",
          "observation_id": "observation-ebrpd-water-quality-current-del-valle",
          "stance": "supports"
        }
      ],
      "observations": [
        {
          "artifact_refs": [],
          "content": "At retrieval, the EBRPD page posted a blue-green algae Caution Advisory for the East Swim Beach and stated that the West Swim Beach had no water because of low lake levels.",
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        },
        {
          "artifact_refs": [],
          "content": "At retrieval, the current-conditions table listed a Caution Advisory for the Del Valle East Swim Beach and no advisory for the West Swim Beach, where it reported no water because of low lake levels.",
          "observation_id": "observation-ebrpd-algae-current-del-valle",
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          "source_id": "source-ebrpd-blue-green-algae"
        },
        {
          "artifact_refs": [],
          "content": "At retrieval, East Beach had a blue-green algae Caution Advisory and West Beach had no water because of low lake levels.",
          "observation_id": "observation-ebrpd-swimming-current-beaches",
          "observed_at": "2026-09-20T00:00:00+00:00",
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          "source_id": "source-ebrpd-del-valle-swimming"
        },
        {
          "artifact_refs": [],
          "content": "At retrieval, the table listed a Caution algae advisory at Del Valle East Beach and no advisory at West Beach, where there was no water because of low lake levels.",
          "observation_id": "observation-ebrpd-water-quality-current-del-valle",
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          "source_id": "source-ebrpd-current-water-quality"
        }
      ],
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        {
          "locator": "https://www.ebparks.org/parks/del-valle",
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          "source_id": "source-ebrpd-del-valle-park-page"
        },
        {
          "locator": "https://www.ebparks.org/natural-resources/water-quality/blue-green-algae",
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          "source_id": "source-ebrpd-blue-green-algae"
        },
        {
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          "publisher": "East Bay Regional Park District",
          "source_id": "source-ebrpd-del-valle-swimming"
        },
        {
          "locator": "https://www.ebparks.org/natural-resources/water-quality",
          "publisher": "East Bay Regional Park District",
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        }
      ]
    },
    {
      "claim": {
        "claim_id": "claim-ebrpd-swimming-del-valle-lifeguard-hours",
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        ],
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          "hours": [
            "11:00",
            "18:00"
          ],
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      },
      "evidence": [
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          "claim_id": "claim-ebrpd-swimming-del-valle-lifeguard-hours",
          "evidence_id": "evidence-ebrpd-swimming-del-valle-lifeguard-hours",
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        }
      ],
      "observations": [
        {
          "artifact_refs": [],
          "content": "The Del Valle swimming page lists lifeguards 11 AM-6 PM on weekends and holidays from May 16 through September 27, two beaches, and year-round swimming without lifeguards north of the boat ramp.",
          "observation_id": "observation-ebrpd-swimming-del-valle-hours",
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          "source_id": "source-ebrpd-del-valle-swimming"
        }
      ],
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        {
          "locator": "https://www.ebparks.org/recreation/swimming/del-valle",
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        }
      ]
    },
    {
      "claim": {
        "claim_id": "claim-ebrpd-swimming-del-valle-monitoring",
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          "evidence-ebrpd-water-quality-del-valle-monitoring"
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        ],
        "subject_id": "program-ebrpd-hab-monitoring",
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          "november_march": "twice_monthly",
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            "blue_green_algae"
          ]
        }
      },
      "evidence": [
        {
          "claim_id": "claim-ebrpd-swimming-del-valle-monitoring",
          "evidence_id": "evidence-ebrpd-swimming-del-valle-monitoring",
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        },
        {
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          "notes": "",
          "observation_id": "observation-ebrpd-water-quality-program",
          "stance": "supports"
        }
      ],
      "observations": [
        {
          "artifact_refs": [],
          "content": "Del Valle beaches are sampled for bacteria weekly April-October and twice monthly November-March, with two sample sites per beach. Posted stop-light signs combine latest bacteriological tests and blue-green algae conditions.",
          "observation_id": "observation-ebrpd-swimming-monitoring",
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          "retrieved_at": "2026-09-20T00:00:00+00:00",
          "source_id": "source-ebrpd-del-valle-swimming"
        },
        {
          "artifact_refs": [],
          "content": "EBRPD routinely monitors recreational and drinking water, storm water, wastewater, lakes and creeks, and responds to sewage, oil, and hazardous-material incidents. Natural swim areas are sampled weekly April-October in collaboration with county environmental-health departments, with current data posted for safe recreation choices.",
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        }
      ],
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        {
          "locator": "https://www.ebparks.org/recreation/swimming/del-valle",
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        },
        {
          "locator": "https://www.ebparks.org/natural-resources/water-quality",
          "publisher": "East Bay Regional Park District",
          "source_id": "source-ebrpd-current-water-quality"
        }
      ]
    },
    {
      "claim": {
        "claim_id": "claim-ebrpd-swimming-del-valle-parking-fee",
        "evidence_ids": [
          "evidence-ebrpd-swimming-del-valle-parking-fee"
        ],
        "predicate": "published_swimming_page_parking_fee_usd",
        "spatial_scope_ids": [
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        ],
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        "temporal_scope": null,
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      },
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          "claim_id": "claim-ebrpd-swimming-del-valle-parking-fee",
          "evidence_id": "evidence-ebrpd-swimming-del-valle-parking-fee",
          "notes": "",
          "observation_id": "observation-ebrpd-swimming-del-valle-fee",
          "stance": "supports"
        }
      ],
      "observations": [
        {
          "artifact_refs": [],
          "content": "The Del Valle swimming page displays a $10 parking fee without seasonal or vehicle-type detail.",
          "observation_id": "observation-ebrpd-swimming-del-valle-fee",
          "observed_at": null,
          "observer": "user-supplied page transcription",
          "retrieved_at": "2026-09-20T00:00:00+00:00",
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        }
      ],
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          "locator": "https://www.ebparks.org/recreation/swimming/del-valle",
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        }
      ]
    },
    {
      "claim": {
        "claim_id": "claim-ebrpd-swimming-del-valle-safety",
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        ],
        "predicate": "swimming_safety_guidance",
        "spatial_scope_ids": [
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        ],
        "subject_id": "lake-del-valle",
        "temporal_scope": null,
        "value": {
          "check_posted_signs": true,
          "days_to_avoid_after_rain": 3,
          "keep_dogs_away": true,
          "keep_water_out_of_mouth": true,
          "shower_and_dry_after": true
        }
      },
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        }
      ],
      "observations": [
        {
          "artifact_refs": [],
          "content": "The page advises keeping water out of the mouth, showering and towel-drying promptly after swimming, avoiding lake swimming for three days after rain, checking posted water-quality signs, and keeping dogs away from the water.",
          "observation_id": "observation-ebrpd-swimming-safety",
          "observed_at": null,
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          "retrieved_at": "2026-09-20T00:00:00+00:00",
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        }
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        }
      ]
    },
    {
      "claim": {
        "claim_id": "claim-ebrpd-swimming-east-beach-in-park",
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        ],
        "predicate": "located_in",
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          "claim_id": "claim-ebrpd-swimming-east-beach-in-park",
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        }
      ],
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        {
          "artifact_refs": [],
          "content": "The Del Valle swimming page lists lifeguards 11 AM-6 PM on weekends and holidays from May 16 through September 27, two beaches, and year-round swimming without lifeguards north of the boat ramp.",
          "observation_id": "observation-ebrpd-swimming-del-valle-hours",
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        }
      ]
    },
    {
      "claim": {
        "claim_id": "claim-ebrpd-swimming-west-beach-in-park",
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        ],
        "predicate": "located_in",
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        "subject_id": "beach-del-valle-west",
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      "evidence": [
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          "claim_id": "claim-ebrpd-swimming-west-beach-in-park",
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        }
      ],
      "observations": [
        {
          "artifact_refs": [],
          "content": "The Del Valle swimming page lists lifeguards 11 AM-6 PM on weekends and holidays from May 16 through September 27, two beaches, and year-round swimming without lifeguards north of the boat ramp.",
          "observation_id": "observation-ebrpd-swimming-del-valle-hours",
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          "retrieved_at": "2026-09-20T00:00:00+00:00",
          "source_id": "source-ebrpd-del-valle-swimming"
        }
      ],
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        {
          "locator": "https://www.ebparks.org/recreation/swimming/del-valle",
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          "source_id": "source-ebrpd-del-valle-swimming"
        }
      ]
    },
    {
      "claim": {
        "claim_id": "claim-ebrpd-swimming-year-round-unlifeguarded",
        "evidence_ids": [
          "evidence-ebrpd-swimming-year-round-unlifeguarded"
        ],
        "predicate": "unlifeguarded_swimming_area",
        "spatial_scope_ids": [
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        ],
        "subject_id": "lake-del-valle",
        "temporal_scope": null,
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          "allowed": "year_round",
          "lifeguard_service": false,
          "location": "north of boat ramp"
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      },
      "evidence": [
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        }
      ],
      "observations": [
        {
          "artifact_refs": [],
          "content": "The Del Valle swimming page lists lifeguards 11 AM-6 PM on weekends and holidays from May 16 through September 27, two beaches, and year-round swimming without lifeguards north of the boat ramp.",
          "observation_id": "observation-ebrpd-swimming-del-valle-hours",
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        }
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        }
      ]
    }
  ],
  "entities": [
    {
      "entity_id": "beach-del-valle-east",
      "kind": "swim_beach",
      "name": "Del Valle East Swim Beach"
    },
    {
      "entity_id": "beach-del-valle-west",
      "kind": "swim_beach",
      "name": "Del Valle West Swim Beach"
    },
    {
      "entity_id": "lake-del-valle",
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    },
    {
      "entity_id": "park-del-valle-regional-park",
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    },
    {
      "entity_id": "program-ebrpd-hab-monitoring",
      "kind": "monitoring_program",
      "name": "EBRPD Harmful Algal Bloom Monitoring Program"
    }
  ],
  "history": [
    {
      "action": "ADD",
      "change_set_id": "wp-20260920-ebrpd-del-valle-swimming",
      "evidence_refs": [],
      "knowledge_gap_refs": [],
      "path": "canonical/v0/sources/source-ebrpd-del-valle-swimming.json",
      "reason": "Add district-wide and Del Valle-specific swimming evidence with explicit applicability.",
      "record_id": "source-ebrpd-del-valle-swimming",
      "record_type": "source",
      "summary": "Add two linked EBRPD swimming sources while keeping district registration rules separate from Del Valle-specific schedules, safety, fees, and current conditions."
    }
  ],
  "navigation": {
    "next_id": "source-ebrpd-diablo-foothills-park-page",
    "position": 36,
    "previous_id": "source-ebrpd-del-valle-picnic-areas",
    "total": 587
  },
  "observations": [
    {
      "artifact_refs": [],
      "content": "At retrieval, East Beach had a blue-green algae Caution Advisory and West Beach had no water because of low lake levels.",
      "observation_id": "observation-ebrpd-swimming-current-beaches",
      "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-swimming"
    },
    {
      "artifact_refs": [],
      "content": "The Del Valle swimming page displays a $10 parking fee without seasonal or vehicle-type detail.",
      "observation_id": "observation-ebrpd-swimming-del-valle-fee",
      "observed_at": null,
      "observer": "user-supplied page transcription",
      "retrieved_at": "2026-09-20T00:00:00+00:00",
      "source_id": "source-ebrpd-del-valle-swimming"
    },
    {
      "artifact_refs": [],
      "content": "The Del Valle swimming page lists lifeguards 11 AM-6 PM on weekends and holidays from May 16 through September 27, two beaches, and year-round swimming without lifeguards north of the boat ramp.",
      "observation_id": "observation-ebrpd-swimming-del-valle-hours",
      "observed_at": null,
      "observer": "user-supplied page transcription",
      "retrieved_at": "2026-09-20T00:00:00+00:00",
      "source_id": "source-ebrpd-del-valle-swimming"
    },
    {
      "artifact_refs": [],
      "content": "Del Valle beaches are sampled for bacteria weekly April-October and twice monthly November-March, with two sample sites per beach. Posted stop-light signs combine latest bacteriological tests and blue-green algae conditions.",
      "observation_id": "observation-ebrpd-swimming-monitoring",
      "observed_at": null,
      "observer": "user-supplied page transcription",
      "retrieved_at": "2026-09-20T00:00:00+00:00",
      "source_id": "source-ebrpd-del-valle-swimming"
    },
    {
      "artifact_refs": [],
      "content": "The page advises keeping water out of the mouth, showering and towel-drying promptly after swimming, avoiding lake swimming for three days after rain, checking posted water-quality signs, and keeping dogs away from the water.",
      "observation_id": "observation-ebrpd-swimming-safety",
      "observed_at": null,
      "observer": "user-supplied page transcription",
      "retrieved_at": "2026-09-20T00:00:00+00:00",
      "source_id": "source-ebrpd-del-valle-swimming"
    }
  ],
  "record": {
    "locator": "https://www.ebparks.org/recreation/swimming/del-valle",
    "publisher": "East Bay Regional Park District",
    "source_id": "source-ebrpd-del-valle-swimming"
  },
  "record_type": "source",
  "related_records": [],
  "sources": [
    {
      "locator": "https://www.ebparks.org/recreation/swimming/del-valle",
      "publisher": "East Bay Regional Park District",
      "source_id": "source-ebrpd-del-valle-swimming"
    }
  ]
}