EAST BENCH SLIDE AREA
The slide area on the east bench of Riverdale City is active and extremely dangerous. The area has been fenced off and identified and marked as "No Trespass", as such stay out of the area for your safety!! Three homes have been evacuated. The City is working with multiple state, county, and other agencies regarding the slide itself and it's ongoing impacts to the neighborhood and the lands below. No further evacuations are contemplated at this time.
January 12, 2018 - WATER TEST RESULTS
This is in response to questions regarding sources of water being "man-induced" in the area of the recent land slide. Shortly after the slide event, Riverdale City and other water purveyors completed several different test activities to rule-out man induced water sources. These inspections and tests have included the following: visual pipeline inspections, pipe line water-pressure tests, residual chlorine testing, pipe resonance inspections, visually inspecting all water meters and valves in the vicinity, sensitive acoustical testing of water lines, and lastly, a STIFF ion test of water. The STIFF ion test was performed upon water delivered by Weber Basin Water Conservancy District to the communities of South Ogden, Washington Terrace, & Riverdale in contrast to water obtained from the land slide toe. This latest test (STIFF ion test) was to compare the ion analysis with water extruding from the slide area to culinary water delivered to all communities, the compared waters are very different in ion makeup and not from the same source...as such, all of the performed tests have again confirmed water emanating from the toe of the slide is not man induced water.
As mentioned above, the most recent water sample test performed was a STIFF ion test. The diagram or ion panel results of this test is shown below; a STIFF ion test is used to show graphical representation of water chemical ion analysis. Essentially, the "finger-print" of water; in this particular case the compared samples have completely different ion or chemical make up. Geo-chemists use these STIFF plots for analysis and presentation of geochemistry data that are particularly useful in hydro-geologic investigations.
The City continues to monitor the slide and working with geologists will be performing a geotechnical investigation of the soil composition. The geo-investigation work will be within the 600 West street itself beginning Jan. 18th. This work will involve drilling rigs performing work directly east (within the street) of the slide impact zone. The resulting geotechnical study will take some time to complete with on-going monitoring of the slide and associated soils through installed piezometers and inclinometers. The slide area continues to be very active and dangerous with additional sluffing of soil highly probable as was noted yesterday; as such the City and other agencies continue to monitor the situation. For your safety please stay out of this area.
To view the geologic emergency report for the State of Utah click here.
Pictures of the recent land slide in Riverdale City along the terrace.