Yup empty woven sandbags. Buy in bulk online or local stores if they got em, usually pretty cheap. Usually 50 lbs, just fill em up with dirt and tie em off. Line them like bricks on the floor where the dirt would most likely wash away too. One layer would prolly be fine. In spring just cut em open and drop fill back up the low spots on the land. Good luck
Something like these: Sandbaggy - Empty Poly Sandbags W/UV Protection - Size: 14" x 26" - Color: Green - Military Grade - Trusted by US Military & National Park Service (100 Bags) https://www.amazon.com/dp/B075LWH47Z/ref=cm_sw_r_cp_api_glc_fabc_Umn0FbCBPR622
Since u only need it for one season just get the cheapest ones you could find. Doesn’t need to be the UV, military grade, blah blah blah ones.
Good luck