Question: where does the water for lake las vegas come from
[{'answer': 'the Las Vegas Wash', 'provenance': [{'wikipedia_id': '2237980', 'title': 'Lake Las Vegas', 'start_paragraph_id': 7, 'start_character': 29, 'end_paragraph_id': 7, 'end_character': 47, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '2237980', 'title': 'Lake Las Vegas', 'start_paragraph_id': 7, 'start_character': 0, 'end_paragraph_id': 7, 'end_character': 192, 'bleu_score': 0.693273218625259, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11602834881632942744}, 'section': 'Section::::History.\n'}]}]