The Grand Prairie Irrigation Project, locally sponsored by the White River Irrigation District (WRID), is constructing an irrigation canal crossing and new bridge approaches along Highway 70 near Hazen. This has resulted in the loss of 1.78 acres of native tallgrass prairie at Railroad Prairie and Downs Prairie natural areas in Prairie County. By law, the ANHC property must be replaced by a similar property due to the Land and Water Conservation Fund (LWCF) federal grant funds used to purchase the original 1.78 acres at the natural areas.

As mitigation for this project, the ANHC has received an additional 4.19 acres at Downs Prairie Natural Area (NA) from the WRID. The new parcels at Downs Prairie NA are the last unprotected tallgrass prairie remnants adjacent to the existing natural area.

Downs Prairie NA is one of the few remnants of tallgrass prairie left in the Grand Prairie of eastern Arkansas (Mississippi Alluvial Plain). The natural area is home to a diversity of wildflowers, including Indian paintbrush (Castilleja indivisa), ashy sunflower (Helianthus hirsutus), and white wild indigo (Baptisia alba). It supports the largest documented remaining population of prairie mole crickets (Gryllotalpa major) in the Grand Prairie. Prior to settlement, more than 400,000 acres of tallgrass prairie occurred across the Grand Prairie region. Today, less than one percent of those prairies remain.