Drainage - Backyard - advised to use plastic sheets to help keep the soil dry?

i recently had drainage pipes installed in my backyard. the pipes are draining to the front street. my yard is all dirt. the landscaper suggest that i put plastic sheets down all over the back yard and put gravel or wood chips on top of it. he called it walking mulch. he said to put the plastic down to keep the rain from the soil right away. he also graded the yard so that the yard is sloped away from my home. has anyone every done this before. he suggest i do it before the next rain which is coming soon. thank you for any advice or comments in advance.