Orlando Reservoir Outlet Works

In August 2011, Two Rivers performed a video inspection of the outlet to the Orlando dam. We needed to test its functionality before we could store water in the winter. Upon video inspection we realized that the current outlet was inoperable and needed to be replaced. The cost of this project was quite extensive; however the Colorado Water Conservation Board (CWCB) has loan programs with low interest rates to help finance such projects. We applied for this program in September 2011, as we plan to rebuild the outlet and rehab other parts of our water infrastructure system. In our loan application we also included the rebuilding of the headgate for the Orlando Reservoir (how we divert water into the reservoir from the Huerfano river and the Huerfano Cucharas Irrigation Company (HCIC) headgate (how we divert water off of the Huerfano river into the HCIC Ditch). This loan was approved at the annual CWCB board meeting in November.

Construction on the outlet to the Orlando Reservoir began in November 2011.  Below are the approved engineering drawings of the project.

 

 

 

Below is a picture of the old outlet being removed and the land being leveled before installation of the new pipe begins.

 

 

 

Ground compaction and soil moisture tests were completed after each level of dirt was moved. The two photos below show a pad foot roller compacting the ground so the correct compaction and moisture levels can be reached.

Once the ground reached the correct compaction and soil moisture levels, the material was staged. Below is a picture of the 30" pipe that will be used.

Assembling of the pipe and setting the manhole were the next steps in the process. Compaction tests also needed to be done before the manhole was set (the manhole is 6' in diameter).

 

 

A few days later the pipe was attached to the manhole; below is the pipe being cut before connecting to the mega lugs.

 

Assembling the pipe to the mega lugs.

Here is a larger picture of the assembled pipe.

We will begin encasing the pipe with concrete next week. This is an extensive process, but we will have pictures to show our progress.

In order to pour concrete there was some prep work that needed to be done. Rebar was built around the outlet structure and forms were set for the pour.

Before the concrete was poured a geotech had to test the batch to make sure it met the engineered specs.

Pouring and leveling the concrete into the rebar.

Forms were built around the pipe so that concrete could be poured and set as engineered.

The first pour to encase the pipe took place on December 30th. Four trucks were needed to complete this pour.

You can see from the picture below the concrete work that was done last week, and how the project is progressing. The second pour will take place this week.

Continuing our progress of the concrete work the second pour took place on January 4th, and the rest of the pipe was assembled.

While we are making progress on construction of the Orlando Dam, it is important that we do not miss any water. Our Engineers have designed a cofferdam that allows us to start partially filling the reservoir. Below is the design for this dam and a graph showing how long it will take to reach this partial fill.

Below you can see the complete concrete work. We will begin backfilling soon.

Below are pictures of the backfill progress.

 

The cofferdam was built. We should be seeing water there soon!

We are continuing with the backfill of the reservoir. As you can see we are making great progress and have had great weather.

The last ring in the manhole was placed on today.

We have identified the borrowing site where we are going to get the rest of the material to fill in the rest of the dam.

Almost to the top of the breach. We should be laying rip rap this week!

Prepping for the geofabric and the rip rap to be laid

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Rip rap almost complete.

We are now working on the outflow ditch from the reservoir and the outlet works. This is how we will release water from the reservoir to our farms.

This is a picture of the complete outflow ditch.

 

There is now water starting to show up in the reservoir.

The temporary cofferdam was removed. We are just waiting on the final installation of the staff gage that will measure how much water is in the reservoir.