Original: After Chiba was chosen as the site for a major Kawasaki Steel factory in 1950, the prefectural government embarked on a large-scale land reclamation program that dredged up large plots of waterfront property for factories, warehouses, and docks.
Simplified: After Chiba was chosen as the site for a major Kawasaki Steel factory in 1950, the prefectural government started a very large land reclamation program. They filled in the water areas to make large, new waterfront properties for factories, warehouses, and docks.