Complex sentence: The city began planning for the massive Gratiot Redevelopment Project as early as 1946, that would eventually cover a site on the lower east side that included Hastings Street--the epicenter of Paradise Valley.
Split into simpler sentences: The city began planning for the massive Gratiot Redevelopment Project as early as 1946. It was planned eventually to cover a site on the lower east side that included Hastings Street--the epicenter of Paradise Valley.