You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "What was the original name of the dam that serves as the northern boundary of the Topock Marsh?" whose answer is Boulder Dam.
Each document should contain about 30 words, and these documents should contain useful information.

Query: northern boundary Topock Marsh dam
Useful Output:

Doc 1: North Dike marks the northern boundary of Topock Marsh, a separate hotspot, where water diverted from the Colorado River enters the wetland.
Doc 2: This site is located on the Havasu National Wildlife Refuge at the southern end of Topock Marsh approximately 1.2 miles (1.5 km) north of the town of Topock, AZ
Doc 3: This site is located on the Havasu National Wildlife Refuge at the southern end of Topock Marsh approximately 1.2 miles (1.5 km) north of the town of Topock, AZ
Doc 4: From Interstate 40, watch for a Havasu NWR exit sign close to the California/Arizona border. Follow the signs to the refuge. To reach Topock Marsh from Needles
Doc 5: Located at the southern end of the Mohave Valley where the Colorado River meets the Chemehuevi Mountains and veers east past the dramatic Needles rock