Eastern Colorado Water Adventures

I've been meaning to make a trip out to eastern Colorado to check out a few reservoirs. More specifically, the sites of two former reservoirs and a reservoir that has the potential to be the second largest reservoir in Colorado, but is instead a pond. I was finally able to get out there last week, leaving early on Wednesday, March 19 and returning the next day. Not nearly enough time, but I'm happy with what I saw.

The first reservoir site I visited was the centerpiece of the former Bonny Lake State Park, located in eastern Colorado outside of Idalia. This park was the furthest east state park in Colorado. Construction of this South Fork Republican River dam wrapped up in 1951, bringing regular water and flood control to the area. Additionally, for over 60 years, water recreation was brought to an area of the state that previously had little.

Bonny Reservoir was fairly modest in size. This diagram illustrates the different capacities of the reservoir. To give that diagram context, here is a picture of the spillway with the former body of the reservoir in the background.

Bonny Reservoir had the capacity to hold a huge amount of water. In reality, the reservoir never came close to reaching the spillway crest. According to the United States Bureau of Reclamation's Hydromet application, the highest in elevation that the reservoir ever got was 3678.10, all the way back on May 17, 1957, just six years after the dam was completed. In terms of volume, the reservoir held as much as 55,034 acre feet on the same day. This is a hair below the advertised capacity 64,200 acre feet.

The reservoir held greater than 50,000 acre feet one other year - in June of 1974. Since then, the maximum content generally got up to somewhere around 42,000 acre feet. In terms of elevation, the reservoir generally topped out right at the gated sluiceway elevation, give or take a foot. Up until 2003, that is.

In that year, the Supreme Court decided that Kansas was not receiving its fair share of water from the South Fork Republican River.[1] It was determined that not enough water was making its way to Kansas based on the Republican River Compact, which was implemented in 1942. After the Supreme Court decision, the debt was initially attempted to be paid by sending more water than usual through Bonny Dam. While more water was sent versus years in the past, it was not enough to satisfy the Republican River Compact.

In the year 2000, the maximum elevation of the reservoir was 3,666', close to the average maximum since the reservoir was filled for the first time. From here, the annual maximum slowly slid as more water was sent to Kansas. The following four year maximums are as follows:

2001: 3,668'
2002: 3,662'
2003: 3,660'
2004: 3,657'

This pattern continued until 2011. After years of deliberation and trying to find an alternative to draining the reservoir, no better option was found. Any other option would have been prohibitively expensive and taken too much time to implement. So it was decided that the reservoir would be drained, with the water ultimately making its way to Kansas to satisfy the Republican River Compact. The draining of Bonny Reservoir began at the close of water year 2011 (September 30) and concluded in April of 2012. Since then, the "reservoir" has fluctuated between zero and one acre feet.

Here is a side by side satellite image of Bonny Reservoir at two stages. On the left is an image of the reservoir from June 7, 1995, and on the right January 2, 2014. In the left photo, the reservoir is at an elevation of 3,674', just above the bottom of the gated sluiceway, and holds 44,866 acre feet. In the right photo the reservoir is at an elevation of 3,638 and holds zero acre feet.

June 7, 1995 on left, January 2, 2014 on right.

I visited the drained reservoir because I was curious. I've seen many full and partially full reservoirs, but never one that was (intentionally) drained. Especially one that was such an anchor in local recreation. Without knowing any better, I started driving over the dam. The first thing that I saw of note was the concrete spillway pictured above.

Back of dam and spillway.

The picture to the right is my favorite that I took from the spillway. The black shadow in the bottom left corner is where the gated sluiceway comes through the spillway. The dam is the hill coming from the right side of the picture and running toward the center. In all, the dam is over a mile and a half long. Interesting that even in the very best year (way back in 1957!), the water barely got six feet high in the gated sluiceway. The dam could have easily been built smaller with a less imposing spillway. It'd be interesting to know what the river was doing to persuade the engineers to go so big.

Other than the spillway, I found the high and dry boat ramps to be most interesting. It's been a couple years since any of the boat ramps were used on this reservoir, and they will likely never be used again. It will take an awfully wet period for enough water to both satisfy the Republican River Compact and fill the reservoir. In the meantime, we will have to make do with the area being turned into a state wildlife area.

North Arm boat ramp

Primary boat ramp

Deepest boat ramp

As a parting shot of Bonny Reservoir, here is the length of the reservoir from the dam. It's hard to believe that water stretched nearly three miles at full pool. Now, a marsh during wet periods.

Bonny Reservoir as of March 19, 2014

Next on my agenda was to travel to Eads to spend the night before heading to my last two reservoirs. Eads is the largest town and county seat of Kiowa County, with a population of just over 600. 

Out of Eads, I took highway 287 south to get to Neenoshe Reservoir. Or what was left of it. As stated by the USGS, Neenoshe Reservoir was created in 1896 with the purpose of conserving water from the Arkansas River. Neenoshe is actually quite impressive in size, at least at the rare times it is full. According to the same USGS document, the reservoir holds a maximum of 94,850 acre feet, with 73,360 being usable. Additionally, the reservoir has a surface area of 4,562 acres at full capacity. For those familiar, Horsetooth Reservoir outside of Fort Collins has a surface area of only 1,900 acres at full pool. For those who aren't familiar, Neenoshe is up to 9 times bigger than the largest natural lake in Colorado, Grand Lake. Neenoshe has the potential to be a big reservoir, especially when combined with the rest of the reservoirs in the area.

Because Neenoshe and the rest of the reservoirs in this clump are privately owned by the Amity Mutual Irrigation Company, there is little information about them. Other than the USGS article already mentioned, I am unable to find more information on the water data of these bodies of water. What I do know about these reservoirs is from word of  mouth and satellite images. The water from these reservoirs comes from the Arkansas River via canals. During the most recent wet period in the late 90s, the reservoirs were mostly full. In an email from Amity Mutual, I learned that on average these reservoirs fill up every twenty years. After the current drought began, the reservoirs shrank as diversion from the Arkansas River ceased. The following picture compares these reservoirs from the last time they were full (no way to know for sure) to their levels less than two weeks ago. 

June 25, 1999 on left, March 14, 2014 on right.

The contrast in water levels between these periods is staggering, and illustrates why I wanted to check this area out. I got here on the start of what was to be a beautiful day. I entered the reservoir from the north entrance and drove down the boat ramp as far as the road would allow. I made it probably a quarter of a mile before the condition of the road forced me to park. I continued to walk from there. Very interesting scene from the bottom.

This is from approximately here in the reservoir. (The Google Map image is from 8/31/2012, which is why there is more water than when I went.) No idea for sure, but I think I'm facing the southeast. At least I meant to. At this point in my walk the silt was very soft and it was physically demanding to walk. Not quite muddy, and not like walking on a beach. I tried to walk further toward the center of the reservoir, but the silt was getting softer and softer. I decided there was not enough to be gained from walking to the center.

Wind-blown surface

North boat ramp on Neenoshe

Before I left, I took this picture of the surface. This picture was taken in roughly the same place as the previous, just a little further towards the center. Very interesting texture -makes me think of a lunar landscape. Not much else to say about this cluster of reservoirs. I really wish I could have had more time to explore this area, but I had about seven hours of driving left to do that day. The picture on the right is from the north boat ramp looking out over the reservoir. Straight out from this picture, the reservoir would have stretched over two miles, and over three miles to the furthest point towards the southeast.There's little about this reservoir on the Internet, but back in 1973 someone did catch a 33 pound catfish (page 10).

Next I headed to John Martin Reservoir. Often forgotten, and incorrectly attributed as the third or fourth largest reservoir in the state by capacity, John Martin sits on the Arkansas River in the southeast corner of Colorado. To clear up the size issue, here is the correct order of the four largest reservoirs by capacity in the state of Colorado:

1. Blue Mesa Reservoir - This is undisputed and fairly well known. Blue Mesa has a live storage capacity of 829,500 acre feet. 
2. John Martin Reservoir - Poor John Martin never gets love. Second largest reservoir in the state with a maximum capacity of 603,500 acre feet at top of spillway gates.
3. Lake Granby - Third largest in state with a maximum capacity of 539,758 acre feet. Often attributed as second largest, occasionally third.
4. McPhee Reservoir - Total capacity of 381,195 acre feet makes this reservoir fourth largest in Colorado by capacity.

While John Martin is the second largest reservoir in the state by capacity, it has never actually reached the capacity listed above. In fact, the most water John Martin held at any one time was 450,000 acre feet for about ten days in May of 1999, which is pictured below. Since then, the water has been as low as 2,800 acre feet. On the other hand, Lake Granby has averaged 364,146 acre feet over the last ten years. I think the remoteness of John Martin and the fluctuating water levels, which trend on the low end, have caused people to not recognize its capacity. And really, capacity is only meaningful if you can actually fill the reservoir, which the other three on this list do regularly. 

It was the fluctuating water level of John Martin that made me add it to the itinerary. I got there sometime around noon after leaving Neenoshe. The reservoir was holding approximately 48,000 acre feet the day I got there. Low, but it had more than doubled since November 2013. The following is a satellite image comparison of John Martin reservoir when it was at its highest and lowest since. 

May 8, 1999 on top; July 30, 2006 on bottom

The reservoir is huge in the top picture. It measures over ten miles from the dam to Arkansas River, and anywhere between 1.25 and 3.5 miles wide. At capacity, the reservoir has a surface area of over 17,000 acres. At the same time, the reservoir is only 80 feet deep at the dam in the top picture. Fairly shallow given that it contains 450,000 acre feet. On the other hand, in the bottom image the reservoir holds only 2,810 acre feet, is about 1.2 miles long, 0.8 miles wide, and approximately 12 feet deep at the dam. The bottom image, unfortunately, is a better representation of the reservoir for the past fifteen years.

There are three concrete boat ramps on the John Martin, all on the north shore. Two of the boat ramps are located on the east end, not too far from the dam. In most water conditions both are usable. If the water dips below about 30,000 acre feet, though, only the furthest west ramp will be in the water. Both of these ramps are in the heart of the state park that surrounds the reservoir. The boat ramp that is the most interesting to me is one furthest west.

This boat ramp is located approximately 6.75 miles from the dam (green arrow). As you may haven guessed from the previous information, this ramp has been high and dry for years, and will likely never see water again, especially enough to launch a boat. I drove down this ramp and went as far as I could toward the river. Turns out the park system put up a gate, blocking people from driving too far into the reservoir bed.

Facing west boat ramp from 1/2  mile away

Here's a picture from about a half mile or so down the boat ramp. On the far side of the red line of tamarisk is where I had to park the car. The concrete stripe in the middle of the picture is the boat ramp. I'm under probably 30-40 feet of water at full reservoir in this picture, maybe more. It's hard to believe that the reservoir used to stretch miles west of this point. There were no signs beyond the boat ramp that this area used to be under water. And why should there be? It's been over 15 years since this area has been wet. My goal coming down this ramp was to walk to the Arkansas River. I thought it would be fairly simple to follow the vehicle tracks down to the river. Turns out I was wrong. Not only did the tire tracks branch off many times and become too thin to follow, but the tamarisk got thicker and thicker as I got closer to the river. Looking at satellite images of the area, it's apparent that I would not have been able to just stroll up to the river like I was hoping. 

Back at the top of the boat ramp, here's the view looking over what used to be the reservoir. At full pool, the reservoir used to be about a mile and a half wide at this point.

Facing dam

The picture to the left is from the western most boat ramp facing the direction of the dam. The boat ramp is at the bottom of the picture, and the current water level is barely visible below the horizon. I really like this picture, as it nicely demonstrates how much longer and broader the reservoir could be.

I'm interested to find out whether or not the reservoir will even be over 200,000 acre feet again. My guess is that it won't ever reach that level again, and probably not even 100,000 acre feet. In its current form, John Martin Reservoir is a very important resource in southeastern Colorado. At nearly any level, it provides valuable resources for the area. As a parting shot, here is the reservoir at 48,000 acre feet as viewed from the dam. Although the reservoir is a shadow of what is has been and could again be, it still provides a decent surface area for recreation.

John Martin Reservoir from dam as of 3/20/2014.