A water source survey was conducted in 1933. The survey investigated and rated the possible sources as follows:
1. Soft water well field southwest of town. (Preferred)
2. Redwood River by means of tiles to shallow wells. (Affected by contamination and dry season)
3. Springs south of Lynd. Estimated cost of running main was $140,000 in 1933. (Cost & Risk)
4. Shallow gravel area wells in 15' depth. (Not adequate especially when dry)
5. Shallow gravel area wells in 64' depth. (Too limited)
6. Current deep 460' artesian well. (Not satisfactory-corrosive and hard)
The soft water area southwest of town was chosen. Layne-North Central Co. was contracted to install a well field to supply water to Marshall Municipal Utilities. MMU choose to not own the new source, but lease it from the well drilling company which charged MMU on a per 1000 gallons basis. In 1935, the lease or rental on the Layne contract was $13,000 and total water utility income was $20,000. In 1939, MMU made the decision to purchase the water system and three wells from Layne-North Central Co. This well field, which was located around the current water plant, solely supplied water to Marshall from 1934 until 1955 and partially until 1976. A total of eight wells were drilled from 1934 until 1954. These wells pumped between 35 100 gpm when first drilled. They received frequent treatments and were abandoned when they could no longer produce. There were typically five or six wells available; however, it was uncommon to have one or two out of service.
In 1939 and 1955, Marshall experienced water shortages and in each case, an emergency well was drilled. The 1955 well was drilled into the shallower glacial deposit because volume became more important than quality.
From 1955 1958, Marshall explored options for more water. Layne was hired to drill and find another well field in the deeper (softer) aquifer. After two years of drilling, nothing was found and the idea of receiving water from the Camden State Park area was revisited; however the expense and corrosiveness made this choice unattractive. A hydraulic engineer was hired to examine using surface water by damming the Redwood River or one of its tributaries. USGS surveys of Lyon county and the area around Marshall did not find Cretaceous sands that could meet Marshall's demand. The decision was made to drill wells in the shallower glacial deposits which is MMU's current aquifer.
The wells toward the north part of the aquifer were drilled in the late 1950s and 1960s. The wells in the south part were drilled in the 1970s and 1980s. In 1960, the first water plant was put into service to remove the higher iron and manganese content of this water.
Bruce Liesch began working with MMU in the late 1960s on expansion of the Marshall Aquifer Well Field through the use of geophysical survey equipment. This equipment is capable of identifying buried deposits of permeable sand and gravel within the clayey glacial drift deposits by analyzing variations in natural electrical earth resistivity. This technique is particularly effective in the Marshall Aquifer where shallow deposits of high resistivity sand and gravel occur within large bodies of relatively low resistivity clay. Generally, the sand and gravel aquifer segments, which vary significantly over short distances, cannot be seen at the land surface making this type of survey a very effective tool to identify potential well sites.
The last new well site was developed in the Marshall Aquifer in approximately 2012 A lot of effort goes into maintaining well yields, replacement of failing wells and development of other sources.
In 1986, information came to light regarding a possible aquifer located east of Marshall and an electrical resistivity survey was conducted to identify potential well sites in what would later be designated the Dudley Aquifer. After a successful testing program, the Dudley well field was developed with MMU Wells 22, 23 and 24 were installed in the aquifer between 1988 and 1991 and the water was piped back to the treatment plant for use in Marshall. Water demand increased in Marshall in the following years through 1996 and several steps were taken to bolster Marshall's water supply.
An additional well was proposed for the Dudley aquifer in 1996 and after extensive discussions with the Department of Natural Resources, Well 26 was permitted as the last well in the Dudley Aquifer with only a minor increase in the overall water appropriation permit.
(CONTINUED NEXT WEEK)