River Des Peres Channel Rehabilitation

RIVER DES PERES CHANNEL REHABILITATION PROJECTS

Since 1966, Reitz & Jens, Inc. has had a long history with the Metropolitan St. Louis Sewer District (MSD) on River Des Peres projects. At that time, an analysis of topography and properties of typical soil strata was performed that affected bank stability. Recommendations were presented to correct known areas of bank disturbance. In 1969, geotechnical investigations including slope stability analyses were performed at four additional locations of bank failures along the lower channel. Corrective measures were developed; bid plans and specifications were prepared. On-site inspection services were also provided during the construction phase of the slide corrections. In 1983, RJ participated with MSD during the Master Facilities Plan Study of the entire River Des Peres stormwater system. Our firm identified several areas of concern as related to outfall and erosion of various channel-connecting stormwater interceptors and creek intersections.

In 1992, MSD retained Reitz & Jens to collect existing data, and perform field inspections. The study included geotechnical investigations, and analyze of the condition of a 6-mile open channel section from the Mississippi River to Macklind Avenue. The results were published in a report titled "River Des Peres Channel Rehabilitation, Phase I Outfalls & Erosion - Comprehensive Study." The study included detailed documentation of each deteriorated area, with recommended corrective actions and an approximate construction cost. It also prioritized each area based upon the severity of degradation, and potential for bank failure affecting other improvements. Based on the study, our firm designed improvements to four of the highest ranked problem areas within the River. Three projects involved replacement of selected sections of the large trapezoidal channel. The fourth involved treatment of a large bank failure, at Arsenal Street, and replacement of an approximately 700-foot section. This slide repair utilized a 3-foot thick trapezoidal channel tied to bedrock to buttress the slide. Due to the project's complexity, Reitz & Jens was retained to provide quality control inspection and testing services during construction. The construction phase included:

• compaction control
• inspection installation
• testing of double corrosion protected rock anchors
• monitoring of slope movements with inclinometers.

The slide repair was successfully completed in 1994, at a cost of approximately $2 million, with no additional damage to the channel.

In 1994, Reitz & Jens provided geotechnical engineering services regarding MSD's Lower Lemay Service Area Overflow Regulation System (O.R.S.). Improvements included additional and upgrading of the pump stations, gate structures, and outfalls along the Lower River channel. These services included:

• analysis of subsurface/conditions for structural support
• slope stability
• erosion control
• dewatering
• buoyancy and building foundations.

The second Phase of the Lemay O.R.S. began in 1995. During construction, our firm provided all geotechnical quality control services for the pump stations, gate structures, and outfall repair/replacements. These services included inspection and testing of all structural subgrades, slope stability improvements, rock anchor installations, backfill and fill compaction.