Waterloo's Electric Park was located on the Cedar River about half-way between the cities of Waterloo and Cedar Falls. It was serviced by the interurban line that ran between the two cities and was in fact owned and operated by a subsidiary of the Waterloo, Cedar Falls, and Northern Railway. The postcards show a bandstand located to the left of the Ferris wheel. The park supported its own "house band" consisting of 16 pieces. The Ferris wheel was unique in that it was a water wheel which was powered by a stream of water at the top of the wheel that flowed into buckets that eventually dumped the water as the wheel turned.
About the park operations
The July 1913 issue of the newsletter Electric Traction (v. 9) offers an interesting account of the operation of a local amusement park at the turn of the 20th-century.
AMUSMENT PARK OPERATION
The Waterloo, Cedar Falls & Northern Railway Company has a well worked out plan for operating its amusement park, Electric Park, which is situated about 1 1/2 miles from the center of Waterloo, Iowa. It is located on the interurban line between Waterloo and Cedar Falls, and is also reached by one of the city lines, being only a short distance outside the city limits. The park property is rented from a private corporation, and the railway company has no money invested in the park whatever, except for lighting facilities. A subsidiary company organized and known as the Waterloo Amusement Company, assumes all responsibility for the park and eliminates all the red tape which would be necessary if the park business, pay rolls, etc., had to go through the general offices of the company.
The Waterloo Amusement Company hires a manager of concessions who is made entirely responsible for, and has general charge of, all concessions, there being about 50 in the park. He pays the company a flat rate on all concessions and has all he makes over this amount. The concessions in the park consist of a figure eight and a roller coaster, both of which will run 100 per cent of the gate attendance, a "squeeze," a circle swing, a Japanese ball game, shooting galleries, etc. They are all let exclusively, and on big days the concessions have the right to put up as many additional stands as they want to, giving them a chance to make money when they can.
The railway company does not believe in a free gate, and charges 10 cents admission to the park for everyone. Free attractions have proven to be a failure with the company, and instead of paying some famous band $1,000 for one week, they now observe the practice of having their own band, consisting of 16 pieces, at a cost of $250 a week. This band is paid rain or shine, and the officials say it is a good one. The amusement company retains the right to operate the theater and dance hall. The latter is the best paying proposition on the grounds, the charge being 10 cents a dance or 50 cents for the evening. The theater, which is a very neat little structure, seats 1,200 people and is run as a four-act vaudeville show with no pictures. This is used as a special attraction to get people out to the park and a first-class 10, 20, 30-cent quality show is given every week and an admission of only 10 cents charged for any seat in the house. They do not make any money on the theater and, in fact, lose some, but this is made up by the gate receipts and the patronage of the concessions. Friday night used to be a very poor night at the theater and in the park generally, and in order to make this night profitable the children are admitted free at the gate and also at the theater, and the Friday night attendance now runs up as high as 2,000, which is good for this sized park. No attempt whatever is made to operate the park in the day time. However, it is kept open for the use of picnickers, and any of the concessions will be run if customers desire. The park is opened up late in the season and closed early, operating approximately from June 1 to September 1. Only one policeman is hired by the amusement company, and he does night watchman work as well. In the seven years the park has been operated there have been only three arrests and there has never been a bad case of robbery or pickpocket. 
The following excerpt is from Ferris Wheels: An Illustrated History (1993) by Norman D. Anderson.
Around and Around Inside a Water Wheel
...[Waterloo's] Electric Park, however, had one ride that is believed to have been the only one of its kind - a water-turned Ferris wheel designed by Quincy Stubbs of Ohio...
Quincy Stubbs filed for a patent on his water-turned pleasure wheel on November 12, 1903 and it believed that he built the wheel at Waterloo's Electric Park soon after receiving his patent (No. 774,209). In a newspaper interview in 1934, Stubbs described the wheel by saying:
"My wheel was all steel, 50 feet in diameter and carried 48 persons. It was an overshoot wheel and required very little water to operate it. The buckets or troughs spilled the water rather high up and as it passed over the vari-colored lights, which I had installed, made a pretty sight."