From 2023 to 2024

December 31, 2023 on Broadway in Denver, Colorado.

It's sorta disturbing how empty one of the busiest spots in Denver is on New Year's Eve. I was pickng up dog supplies on my monthly supply run. Next stop.... Englewood Walmart for my own supplies. That gave me a chance to recap the end of my recent Little Dry Creek hike and take some pictures of that end in daylight. I'm working on that long blog, which will be out soon. I'm also running some analyses on water from the creek and I'll be reporting on that and rock identification. In short, I'll be wrapping up my explorations of the local geology. 

Two are upcoming. I want to visit the Denver Museum of Nature and Science before I'm done and I'm planning to hike from Center City to Idaho Springs for a look at Colorado's Mineral Belt. Of course, I'll continue to occasionally look at local geology and chemistry as I work on the LabBooks.

Cherry Creek is calling to me. I'll be hiking it's length instead of Station-to-station hikes next year. Denver's history is concentrated along it's banks and it draws wildlife to it's waters. It's also unusual in that it's been a major waterway for Denver but it isn't a mountain river. It rises from the Palmer Divide just north of Castle Rock. I expect an exciting serial hike.

My adventures will be segueing to biology in 2024. Paleontology provides a natural path to biology, zoology, botany, medicine and bioengineering. That means I'll be starting some new LabBooks.

So, one last requisite shot of the Rockies for 2023.

What adventures are you planning for 2024?

Little Dry Creek: The Grand Tour

I've mentioned that I like following waterways from beginning to end. I've finally gotten around to following the neighborhood stream, Little Dry Creek, from it's head near Yosemite and Arapahoe, to it's mouth near Dartmouth. I almost finished early enough to photograph the river end but, alas, it was quite dark when I got there.

I started at the spring behind the Safeway offices. Everything above that is runoff.

My elevation was 5720 feet according to my topographical map. Air temperature was 74.7° F so I was shedding clothes. The stream water was at 3.5° C. It was coming directly from the Dawson formation so it was cold. I'm flip flopping between Fahrenheit and Centigrade because most weather is reported in Fahrenheit but I like to know how far above freezing things are. Water freezes at 0° C.

I tried to get an idea of the flow rate when I took samples for later analysis. I measured approximately average depth and width and tried to clock a piece of balsa wood floating downstream. But the wood wouldn't move. The flow rate at all three sites was "a trickle". I know that the water was moving because it was flowing over the weirs 

The stream here was two inches deep and 12 inches wide.

The Dawson aquifer isn't very productive and having watched the flow rate recorder by the gauge near Arapahoe (It has been nonfunctioning for a couple of months now) and keeping an eye on the spring, it looks like the flow rate responds to rain fall and snow melt almost entirely. 

A network of runoff channels between Yosemite and Alton Way carry Stormwater into Little Dry Creek for and initial boost. The creek shows a good start at valley building.

This view is just west of Yosemite from the spring at the beginning of the Little Dry Creek Greenway. From here on, rocks and weirs (overflow dams) have been added to the bed and shoulders to manage erosion.

Any large rocks in the area are primarily brought in for landscaping and erosion control, so this is not a good area for studying the indigenous bedrock. The top soil is shallow and the underlying material is clayey, weathered bedrock. The bedrock is colluvium, the pulverized material washed out of the Rockies that filled the Denver Basin in recent geologic times 

My second sampling site was between Little Dry Creek Park and Uinta Street. The banks of the stream are steep and there are several slumps where gravity is pulling chunks of the bank into the creek. Closer inspection show these slumps to be saturated with water. They look like seeps, slow moving springs from the underlying Dawson aquifer.

There was a small slump that was just big enough for a foot and a knee. I knelt on that to take a temperature reading and water sample. The temperature was 6.6° C. Trying to stand, I overbalanced and went in head first.

I came out really quickly 

Little Dry Creek is polluted and smells bad. I hoped that the rest of the ten mile hike would give me a chance to dry and air out. On the train back home, no one looked particularly offended so it must have worked.

The water here was 3 degrees warmer than at the spring. I would be tempted to credit that to kinetic energy of flow but it probably had much more to do with the amount of surface area exposed to the sun. The creek was 50 inches wide there. The depth was 14 inches (just enough to totally submerge me and make me actually swim to get out.) Air temperature was down from the spring....68° F., about 7 degrees colder.

This was where I gave up trying to measure the flow rate by throwing chips of balsa into the water. There was flow. Water was trickling over the weir downstream, but the surface was dead calm. There was an active storm sewer dumping into the creek upstream and the aquifer was adding volume at the seeps.

The creek is geologically young but the material under it is clayey debris and crumbly arkose sandstone so it has no problem cutting into it. The whole length has vertical banks from 2 to over 20 feet high, moderate meanders, and a broad valley.

Here's a topographic view of the first quarter of the course of Little Dry Creek from "Highlands Ranch Quadrangle, Colorado, 7.5 minute series." If you're not familiar with topographic maps, the brown lines are elevation contours. The closer they are, the steeper the incline. The v-shaped contours around the creek point upstream.

One advantage of this hike is that it follows a creek that's flowing downhill. There's not a lot of "up".

The third (and last) sampling site is a pretty little cascade just before Spruce Street. It's not "natural". Those granite and gneiss boulders were artistically placed there by Parks and Recreation workers. They did a nice job. A culvert empties an intermittent tributary into Little Dry Creek below where I sampled. (See the blog "Walnut Hills: The Big Hill")

Little Dry Creek was colder here (3.4° C), almost as cold as at the spring. That's interesting since the air was warmer (68.2° F) than at the second site. And I would have expected those rocks to have been soaking up sunlight and transferring the heat to the water.

The stream was 112 inches wide here and 16 inches deep. Of course, the stream dimensions can change but there was no reason for big fluctuations Little Dry Creek is historically pretty consistent, so it's reasonable to compare them from site to site. Within about half a mile, the stream has more than doubled. Runoff isn't large so I'll assume that it's being fed by that aquifer.

Past Quebec, Little Dry Creek flows through an HOA, requiring a detour up to Arapahoe and down to where the stream emerges from under Arapahoe to continue it's journey into Holly Reservoir. The approach is over a series of weirs (the area is always flood conscious) that parallel the road.

There used to be a pedestrian tunnel that passed under Arapahoe beside the creek, but they closed it off before I moved to the area over three years ago. People must have still tried to use it, because the county then covered the approach ramp with crushed granite.

Holly Reservoir (by Holly Road) is home to a recreational center with tennis courts, a swimming pool, and water slide. The creek meanders it's way through the basin and under the dam. In the case of a massive(!) storm, there could be a lake here. I can't find any record of there ever having been such an event but better safe that sorry.

Holly Dam

Little Dry Creek at the outflow of Holly Dam

Just below Holly Dam, Little Dry Creek and Willow Creek merge. Usually the resulting Creek takes the name of the larger stream, but not in this case. Willow Creek is usually larger, has traveled further, and occasionally will create a lake behind Englewood Dam but the creek that flows from this confluence is called Little Dry Creek.

That's Willow coming in from the left.

In this stretch, Little Dry Creek widens out and cuts a fairly deep gorge. There's also a steepening incline.

The Highline Canal leaves the mountains in Watertown Canyon and flows under the influence of gravity for 66 miles (in the past as much as 71 miles) to the Rocky Mountains Arsenal in northeastern Denver. Along the way, it crosses several natural streams, including Little Dry Creek. It does so by following lines of elevation contour. Natural streams generally cross contours at right angles. The crossings present engineering problems.

There are several places where the canal crosses over streams on water bridges called "aqueducts". The photos above show the syphon where the canal crosses under Little Dry Creek. I would have taken a picture from the top except the canal usually doesn't flow during the winter months.

The canal flows into the tunnel from the left (south) and exits a little lower from the right (north). It works pretty much like syphoning gasoline (or any other fluid) from a tank. The starting level is above the outflow level, so the syphon doesn't have to be primed, which is good since the canal is dry for most of the year.

Little Dry Creek is temporary home to many water fowl. Ducks are common but I've seen many others including egrets and herons. They don't usually make themselves at home but they visit often.

After a brief run down between a meander in the Highland canal, the creek takes off through backyards in Cherry Village, so I had to start some road work down Orchard and Long to University Boulevard where I picked it up again near Quincy. From there, it's an urban aqueduct, flowing between concrete walls.

It feeds some private lakes...

and water features in a golf course.

but most of it looks like this for the rest of it's course.

This is South Denver and Englewood with many shopping areas and apartments so flood control is pretty tight. As many tributaries that have joined the creek, I would not be surprised to see it clear its banks (I've never seen it but I wouldn't be surprised.) It doesn't get water directly from the mountains so the main thing that leads to flooding, melting snow pack, isn't that much of an issue.

Concrete culverts don't really draw me, but there are some points of interest here 

This was a surprise to me. I have seen many of the early sites of gold finds...Clear Creek, Montana City, Bear Creek confluence with the South Platte. These are all streams from the mountains. They erode mineralized, crystalline rock. This first significant gold find was from Little Dry Creek, a creek that runs it's entire course through the debris that has been washed from the Rocky Mountains. That means that a pocket of gold must have collected somewhere by an ancient stream, waiting until Little Dry Creek found it and washed it down to present day Englewood where it waited for William Green Russell to come along from Georgia to pan it out. Why was he even looking here?

Nearby, the creek runs below ground to travel under the Englewood shopping district.

By the time I got to the other side, it was too dark to finish photographing the last section of Little Dry Creek, but a couple of weeks later I made a supply run to the area and finished the tour.

The tunnel in the background is where Little Dry Creek emerges from underground in Cushing Park. Here at the confluence with a drainage stream from the park, it looks like a rushing mountain stream. It's landscapes....the rocks were placed.... there's no telling where they're from. They're there to prevent erosion of the bank.

A little further down the rocks give way to a concrete channel as the creek passes under the railroads and the CanAm Highway (Santa Fe) on its last approach to the river 

The underpass is decorated by a mural by Boulder muralist and graphic artist Amanda Wolf (2021).

An overlook over the South Platte River gives a good view of the confluence.

You have to cross the river by the nearby footbridge to see the mouth of the creek 

There's a low overflow dam just upstream.

At the river, I checked the elevation again and found it to be 5256 feet. That's an elevation loss of 464 feet. I'm glad it was mostly downhill.

So that's the Little Dry Creek from beginning to end. I'll be saying more about its contents. And I'll show you some rocks I encountered along the tour.

Have you ever followed a creek from beginning to end? Do your homework first and stay safe.

Louisiana-Pearl Station to Broadway Station: A brief coda.

Back at Louisiana-Pearl Station, I wasn't waiting for a train this time so I had time to play with the Strange Machine. The plaque explains that it is a homage to the guru of tubology and tube bending technology. The afore mentioned guru is the sculptor, Ira Sherman's mentor, Ron Strange.

The Strange Machine is a 3,500 pound kinetic structure that can be set in motion by turning a steel orb. The orb doesn't go 'round and 'round, but back and forth. It takes a little umph but it does work.

After convincing myself that the mass of tubes and neon actually does move, I headed to street level to follow the E and F lines to my final destination (for the time being) in the station-to-station hikes. I've hiked from Watertown Canyon to Union Station and beyond, through downtown Denver and Five Points, Golden to Auraria West, Wheat Ridge and Westminster to Union Station, and around all the light rail terminals, plus Boulder. After this hike, I will give the light rail a rest and change channel....the next channel being Cherry Creek. There's something that likes (to paraphrase Robert Frost) following a large stream from beginning to end 

There are very few places in Denver that is far from murals. This one is across the street from the light rail station. It's called "Furtherrr" and is by the trio, Mars-1, Damon Soule, and Oliver Vernon. It's an interesting piece in that it's hard to focus on any particular part of it.

This is the requisite shot of the Rockies for this hike. Just a little further, Interstate 25 converges on Broadway and the light rail at Broadway Station. That's Long's Peak in the distance.

Near Broadway Station, Broadway is mostly high rise apartments but it's a major north-south thoroughfare through Denver with a lot of interesting spots such as the Gothic Theater, the Brutal Poodle restaurant, Denver Biscuit Company, the Wizard's Chest, a lot of museums, Civic Park, and Natural Paws (the pet store where I usually shop for Vincent's treats and food.)

I-25 and Broadway Station is a major hub in Denver's light rail system. Lines from the southeast and southwest Denver Metropolitan area converge there with lines to downtown Denver. In addition, it's only a block away from Santa Fe Boulevard and Broadway and the parking lot has four bus gates. 

Also, it has one of the best panoramic views of the Rockies and the foothills in Denver.

The Pedestrian Bridge to Nowhere...one end is on a fenced in construction area and the other just hangs in mid air. It's been there for a few months. I guess it might one day join the lot next to Broadway Station to Santa Fe. That would be nice, but, for now, we can make jokes about The Pedestrian Bridge to Nowhere.

So ends my tour of the western lines of Denver's Regional Transportation District light rail. I've seen cool things that I would not have seen had I not been on foot...met cool people.

I'm not sure what I'm going to do with the eastern lines. Many of the stations are too far apart and embedded in industrial areas to provide very satisfying hikes. I'm thinking that I might want to tour the individual stations and hike between selected pairs of stations. The lines in question connect Thornton to Denver and form a loop with the E and F lines out into the plains and to the Denver International Airport.

But my next adventure will be to follow Cherry Creek (in sections) from it's confluence with the South Platte River in downtown Denver to it's origin near Castle Rock. It's a large geologically and historically interesting valley.

There's something that likes following a large stream from beginning to end. Join me.

Walnut Hills: The Big Hill

One thing has drawn me since moving to Walnut Hills. Why is the big hill there?

At Uinta Street, just behind Walnut Hills Elementary School, Little Dry Creek suddenly takes a dive of about 20 feet in the length of a football field. The ridge that the creek cuts persists north to south throughout the neighborhood. It begs the question, "Why are you here."

It has a double peak. If you're walking from the west along Arapahoe road, you hit a steep incline at Spruce Street that peaks and then slopes down a little to the intersection with Uinta, and then it continues up to the top of the ridge between the South Platte and Cherry Creek valleys. It makes me think that Greenwood Plaza Street and Uinta follow an old stream bed. I've speculated that a branch might have cut down from present day Fiddler's Green and the confluence with Little Dry Creek might have increased the erosion down Walnut Hills.

So, I've been looking for an old branch that might have run along current Uinta Street. Then, I remembered that steep declines will usually migrate upstream and I started looking downstream from Uinta. An old topographical map showed me what I wanted.

The map above was cropped from the United States Geological Survey topographical map "Highlands Ranch Quadrangle, Colorado, 7.5 minute series." These maps are put together from data from different sources. The hydrologic data from this map is from a 2011 data set. The tributary that flows down from Fiddler's Green is no longer on the surface. I've never seen water there.

On the last station-to-station hike, I made it a point to trace the path of the intermittent stream on the map that is shown crossing Arapahoe near Uinta.

This is a view from Fiddler's Green Circle just east of where Greenwood Plaza crosses it. The building on the left is the Kaiser Permanente IT building and to the right is the new Junior Achievement building. Between is a depression that features a pond and a preserved wetland.

There are a lot of water features characteristic of Denver urban landscapes around Fiddler's Green. According to the map, there is a spring. That and storm runoff has to go somewhere and the storm sewer surfaces behind the Junior Achievement Building.

Water features usually have purposes in addition to beautification. Water runs into this pond from a storm sewer outlet and is then cycled through the fountains, then it runs under the driveway into the depression beyond where some returns into the sewer system but much of it soaks into the ground.

It's a miniature water treatment plant.

Many of the microbes that get into ground water to cause problems are enteric, anaerobic species like escherichia coli and strains of pseudomonas....bacteria that normally inhabit the guts of mammals but get transferred from toilets and washed out of farms. Being anaerobic (which literally means they live away from air), they don't like oxygen. The fountains oxygenate the water and kill many of the trouble makers.

Also, ground is an effective water purifier. People who camp have heard a lot that running water is safe to drink. Don't believe it. Deep well water is generally safe to drink and spring water directly out of the ground miiiiiight be safe. The idea is that many contaminants are filtered out of water by soil. There's even some ion exchange that goes on when water percolates through certain kinds of rock (some of the more expensive water filters are packed with ion-exchange resins), but some contaminants won't come out regardless of how or how much you filter it. With all the mines upstream from where I live in Colorado, heavy metal contaminants should always be suspected.

But, that said, water filtration is an important part of water purification, and swampy depressions like this, as long as the water doesn't stagnate, are intentionally designed to help purify storm runoff. Even the plants are chosen to help purify the water.

Greenwood Plaza follows the old stream bed closely, so where is the stream now?

Many streams in urban areas are diverted underground into the storm water system. 

I see that in the mid-1880s, the pioneer Rufus Clark developed this area for occupation and there was actually a reservoir here where Arapahoe Plaza now stands. It wasn't a sufficient water source until Castlewood dam was built near Franktown and more water was piped in. So this spring has never been particularly productive (it's the same aquifers that feed Little Dry Creek.)

John and Marjorie Madden, the art patrons associated with the Denver Outdoor Arts Museum developed the Greenwood Plaza area east of Interstate 25 in the 1970s. 

According to the 2008 annual report  published by   Southeast Metro Stormwater Authority,  the Arapahoe Plaza storm sewer was put in the summer of 2007. That would have diverted the intermittent stream underground.

The stream resurfaces for a short distance at the intersection of Greenwood Plaza Boulevard and Arapahoe road. Then it passes under Arapahoe.

Across from the shopping center, there's a library (the Castlewood beach of the Arapahoe public library system) and a bank. The old stream bed is still visible between although the stream itself is now underground.

There it is.

There's even a footbridge over the dry stream bed.

The old stream bed curves around the bank parking lot and runs between that and the Briarwood residential area.

I'm sure some water gets into this area after a heavy rain, but I've never seen any running water here. It looks like this whole channel was carved out by the old intermittent stream before the sewer lines were laid.

From the opposite side of Little Dry Creek, you can see the depression and line of vegetation between two residences between which the old stream ran. The sewer line dumps into Little Dry Creek right here.

There is a small cascade here. It's been reinforced to reduce erosion around Spruce Street.

I can imagine the South Platte River notching out a hanging valley where the Little Dry Creek entered it....maybe ever an impressive waterfall....as the Rockies rose and erosion began to fashion the broad South Platte Valley where Denver would later be built. The tributary would wallow out it's own valley in which the cataract would travel upstream. Present day gulches (actual gulches) exist along the stream's course in several places, such as along Hampden and below the confluence of little Dry Creek and Willow Creek.

But it's above Spruce Street where the little stream has sawn through the big hill at Uinta Street. I would imagine that the little stream from Fiddler's Green helped.

Water plays a major part in crustal geology. It carves the land we see around us and under us, even in very dry regions. As crust is subducted at the edge of continents, water is pulled down with it and alters the recycling of rocks. It's intimately meshed with life and economy. I'm fascinated by the course that water runs on the Earth. 

You can learn a lot about geology by following the water. I plan to follow Cherry Creek, one of two major streams in the Denver area, from beginning to end. Do you have any favorite streams close by?