General hydrological maps: 1/A/1. Hydrographic map of southeastern Wisconsin showing lakes and streams / Wisconsin Public Service Commission -- 1/A/2. Map of Wisconsin showing major sources of stream pollution, 1925 -- 1/A/3. Reservoirs in Wisconsin / Railroad Commission, 1927 -- 1/A/4. State of Wisconsin: water resources planning, 1931 -- 1/A/5. Wisconsin dams, 750 T.H.P. or more / A.T. Lenz, 1937 -- 1/A/6. Hydrographic map of Wisconsin showing major streams and drainage basins and hydroelectric power dams within the designated region, 1938 -- 1/A/7. Rainfall map of Wisconsin, mean annual precipitation 1892-1926, 1945 (3 copies) -- 1/A/8. Water-resources investigations in Wisconsin, 1975 -- 1/A/9. Wisconsin wetlands, 19th century. 1974 -- 1/A/10. [Hydrological map of Wisconsin] (2 copies) -- 1/A/11. State of Wisconsin hydrographic map showing lakes, streams and drainage area boundaries, 1936 (2 copies) -- 1/A/12. State of Wisconsin hydrographic map showing lakes and streams, 1964 --
Erosion maps: 1/B/1. Reconnaisance erosion survey of the state of Wisconsin / Soil Conservation Service, 1934 -- 1/B/2. Wisconsin erosion, 1935 -- 1/B/3. Soil erosion in Wisconsin / A.T. Lenz, 1937 --
Drainage maps: 1/C/1. Proposed drainage basins / Adolph Kanneberg -- 1/C/2. Major drainage areas in Wisconsin used in stream pollution control activities -- 1/C/3. Water resources, guaging stations and drainage basins, 1935 -- 1/C/4. Map of drainage control in Central Wisconsin / Work Division, Wisconsin Emergency Relief Administration, 1935 (2 copies) -- 1/C/5. Project flowage map for the Central Wisconsin Game Project, 1939