Extended Data Fig. 6: Representativeness according to hydrologic regions.
From: National assessment of river protection in the United States
(a) Percentage of river length protected according to different classes of the Protected River Index (PRI) (colored sectors; right) within hydrologic regions (Hydrologic Unit Code 02) and (b) percentage of total river length across hydrologic regions (white sectors; left). The map in (c) illustrates the spatial distribution of hydrologic regions.
