1968 300mw Mossyrock Dam on Cowlitz River creates Riffe Lake near Mount Rainier, WAS

(Satellite)

Dec 2025 Flood

Dec 15, 2025:

Facebook Reel

Four days later, they still are not using the fourth gate.

Facebook Reel

Keith Carrol, Jul 2020

This double curvature arch dam is 365' [111m] above riverbed and 606' [185m] above bedrock. [mytpu]

Each unit is 150mw.

8:14 video @ 9:45
Learn about how we rebuilt the Mossyrock powerhouse generators.

This video must have been taken around 2010. The lake level was lowered in 2017 because seismic issues were discovered. It will be at least until 2031 before they can fix the issues and restore the lake level. [mytpu_whoops] In the meantime, they can't make full use of those new generators.

@ 8:14

I wonder if the Dec 2025 rains would have caused serious problems if the lake had not been lowered because of seismic  issues. It is a shame they have to dump the water quickly rather than let it drain through the generators.

The Chronicle posted 0:26 video

Water cascades through three of the Mossyrock Dam's four spillways as Tacoma Power staff slowly drain a swelled Riffe Lake following last week's atmospheric river event.

According to the National Oceanic and Atmospheric Administration's (NOAA) lake level gauge, Riffe Lake's level is currently at 755.93 feet. From Dec. 7 through Dec. 14 during the storms, the level rose from around 720 feet up to almost 760 feet.

Video by Chronicle reporter Owen Sexton.

1898,1994 Glimmer Glass Bridge near Manasquan Inlet at Brielle, NJ

(Archived Bridge Hunter; Bridge Hunter; Historic Bridges; Satellite)

I classified this as a trunnion bridge because the span does pivot on a trunnion. But I added the label "bridgeRare" because it doesn't use the usual counterweight design.

Metrotrails posted

The Glimmer Glass Drawbridge is one of the only counterweight draw bridges of it's kind, located near the Manasquan Inlet, a section known as the "Glimmer Glass" at the Jersey Shore.

The cable lift Bascule bridge featuring rolling counterweight design was built in 1898, and may be the only surviving bridge of its kind in the eastern US.

The Glimmer Glass is a navigable, tidal channel of the Manasquan River between Manasquan and Brielle, Monmouth County NJ.

Metrotrails shared

Street View, Feb 2022

Street View, Aug 2017

Street View, Feb 2022

2009 Ben Eriksen Flickr via Bridge Hunter, License: Creative Commons Attribution-NonCommercial (CC BY-NC) 
"A VERY Tight Fit"

HistoricBridges, Photo credit: Elaine Deutsch, 2016
"Bridge Status: At risk for demolition and replacement."
The 279' (85m) long bridge has a movable span of 34' (10.4m).
"This is the last known surviving example of a Belidor type bascule bridge in the country. Despite never being common here, this bascule type was also built in Australia where they called it the 'American' type of bascule bridge which is ironic since the type is nearly extinct in the United States today."

He doesn't fly the drone on the other side where we would have a clear view of the curved ramp.

Photography By Gregory Coraggio 5:29 drone video via HistoricBridges

The 17-span bridge is composed of 16 timber stringer spans supported on braced timber pile bents and a 31'-long cable lift bascule rolling counterweight movable span. The single-leaf movable span is a deck girder with an open steel grid deck installed in 1962. A cable attached to each side of the toe end of the movable leaf passes over a single-track sheave atop the braced timber tower columns with braced curved tracks on the side opposite the movable leaf. The opposite end of the cable is attached to a connecting hanger that joins the shafts of the rolling counterweights positioned in series on the track. The two topmost metal counterweights have a solid center guide while the last one has disk guides. The track has built up wood end stops. The tower columns are braced with wood struts on the sides and wire rope stays on the back. The toe lock is manual. The bridge is controlled from an operators house on the upstream side. An electric motor mounted atop the upstream tower column brace engages the drive shaft to turn the sheaves which cause the counterweights to start moving down the track. The motor reverses the action to close the bridge. The operators house, like many elements of the bridge, has been upgraded over the years, but its function and profile are original.

History: Bascule span installed 1938; bridge modified in 1949-50, 1957-58, 1963, and 1971

[ArchivedBridgeHunter]

1923+1957 US-90 Bridges over Pecos River west of Comstock, TX

1923: (Archived Bridge Hunter; Bridge Hunter; no Historic Bridges; Satellite, the bridge was destroyed by a flood on June 26, 2954)

1957: (Archived Bridge Hunter; Bridge Hunter; no Historic Bridges; Satellite)

2013 photo by Nathan Morton via BridgeHunter_1957

The Pecos River is still skinny because the Lake Amistad Dam was not built until 1969.

Chris Spear posted
The "new" U.S. 90 bridge over the Pecos River canyon under construction in this photo circa 1956. Located about 40 miles west of Del Rio, Tx. Previous river level road crossings had all been washed away in flash floods. Note the workers atop the concrete pier.

The bridge in the valley in the above photo must have been a construction bridge. The original US-90 bridge was further downstream at what is now a boat ramp. The road down to the boat ramp was the old US-90.

Satellite

This is a mix of two topo maps. The black line is the old US-90 and the red line is today's US-90.

1944 Mouth of Pecos Quad @ 62,500 and 1972 Seminole Canyon Quad @ 24,000

TXDOT via BridgeHunter_1923

This shows how the road had to climb along the side of the canyon.

BridgeHunter_1923

UP/MoPac/C&EI Bridge over Salt Fork near Sidney, IL

(no Bridge Hunter; no Historic Bridges; Satellite)

Carol Erb posted
1903. Building the C&EI bridge over the Salt Fork, near Sidney, Illinois.
Chicago & Eastern Illinois Railroad Historical Society shared

Carol Erb commented on her post

Miami & Erie Canal Lock #9 in Piqua, OH

(Satellite)

Miami & Erie Canal Overview

Justin Beebe, May 2021

They built the pavilion and restored the lock as an access ramp. Note the notches in the walls for the lock gates.

Rylan Stoltz (cdt_squirel_yt), Sep 2025

The lock was excavated and officially opened on Jul 18, 2024. [GambleAssoc]

The ramp in the lock allows users of the Great Miami River Trail to access downtown Piqua for food and potty. It also provides a connection between the Great Miami River and Ohio to Indiana Trails. The Ohio to Indiana Trail follows the abandoned Pennsy Panhandle route, including their bridge over the Great Miami River.

Satellite

Like the Ohio & Erie Canal on the east side of Ohio, this canal was severely damaged by the 1913 flood, which caused it to close.

Matthew Good, Jun 2019

Mud Mountain Dam on White River near Enumclaw, WA

(Satellite)

Dec 2025 Flood:

Facebook Reel

Most big dams have multiple functions. This one has just one function --- flood control. This is the upstream side of the dam and the reservoir is empty except for the normal flow of the river.

USACE
"The core of the dam is a compacted blend of sand, gravel and glacial till. Upstream and downstream sides of the dam are crushed rock covered by large quarry rocks. The massive weight of the rock holds the core firmly in place. Two tunnels channel the river around and under the dam. A 9-foot-[2.7m]wide tunnel passes normal flows [including sediment]. A 23-foot[7m]-wide tunnel is used during periods of high flows and during floods."

This view is from the other side and it shows that the dam is holding a pool.

USACE

This is a comparable view but the pool is empty. Note that the pool above is almost to the top of the round tower.

Rajesh Kodali, Aug 2021

 Rajesh Kodali, Aug 2021

Why can't the fish use the 9' (2.7m) tunnel to pass through the dam?

$112m was spent for a trap-and-haul facility for the Chinook run. [USACE]

USACE, Seattle District posted
Mud Mountain is a "dry bed" dam with a primary goal of remaining as empty as possible. During a drawdown here, our water managers must also manage sediment and debris. Using specialized tunnels, we "flush" glacial flour (fine-grained, silt-sized rock particles) and wood through the dam to maintain the reservoir’s capacity and ensure the White River’s natural ecosystem remains healthy.

I could not find an explanation of what gets flooded downstream at the various phases of discharge.

KingCounty

Michael Snyder tweeted
White river from Mud Mountain dam release, still flooding local areas and may get worse in Auburn/ Kent areas. 

2:15 video @ 0:21
The person being interviewed says the river is higher than he has ever seen before.

TP&W Farmdale Bridge over NKP/LE&W near East Peoria, IL

(no Bridge Hunter; no Historic Bridges; Satellite)

At first, I was confused by the skinnypiers in the middle and the fat piers on the edges.

Street View, Aug 2011

But these photos confirmed that the skinny piers are parallel to the NKP tracks while the fat piers are square with the TP&W tracks so that they can be smaller.

Noah Haggerty posted four photos with the comment: "An eastbound Toledo, Peoria & Western mixed freight led by three different EMD locomotives cross over the N&W at Farmdale Bridge around late 1979. On the rear of the train, SW1500 #305 is giving the train a push up Washington Hill. John & Roger Kujawa Photo, Thomas Dyrek Collection."

David Jordan: The single TP&W unit makes me wonder if this was the Watseka trip one week after the LaHarpe/Keokuk move? I saw both back then.

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2

3

4

Mark Zook commented on Noah's post
I took this photo, however, it was back when I lived in East Peoria prior to moving to Florida. I believe it was around 1976 or 1977.

Noah Haggerty: Mark Zook Sweet photo! Exact dates escape me, 765 was first on the TP&W in May of 1980.

Mark Zook commented on his comment
here’s another photo. I was chasing the train.

This map helped me find the bridge

1950/50 Peoria East @ 24,000

The NKP route was the western part of the Lake Erie & Western.

Rails and Trails via Dennis DeBruler

1932 Prettyboy Dam on Gunpowder River near Parkton, MD

(Satellite)

kiddle
"The Prettyboy Dam was finished in 1932." The reservoir and the forests around it are owned by the City of Baltimore because it is part of its water supply. "There's a story about how Prettyboy Reservoir got its name. It's said that the lake was named after a settler's horse, named Pretty Boy. The horse supposedly drowned in a creek that was once in the area."

The water dissipation technique for the far spillway is different than the middle two. A closer look at the above photo shows the outer two spillways curve into an apron while the middle two just drop down into the river.

yelp, Ana B. on Mar 10, 2024

This view clearly shows that they run the outlet works while spilling water.

AmericanWhitewater

Down the Gunpowder River posted
If you've walked up or down those almost vertical stairs in Parkton, MD., You have found one of the sources of the Gunpowder River coming out of Prettyboy Dam.

Tim Feeser: Back in the 1970’s, the water flow was held to a trickle in the summer. Thanks to Trout Unlimited and some cooperative folks in Baltimore, a minimum flow agreement was reached. This was the genesis of the year round trout fishery we have today.

176 steps [overview]

Kimberly Moore commented on Daniel's post
This is a picture from my son’s drone. Spent many years there hiking and swimming.

 

reddit, RusselStrouseStudio (also Instagram)

Note that the outlet works is running in every photo of the dam. The outlet works removes the water from the lower depths of the reservoir where the water is colder. The cold water and constant flow is probably to help the fish. 

This information confirms my fish theory and informs us that the fish are trout. It also informs me about Google's relatively new AI application. I read that some websites are suing Google because people are no longer "clicking through." That is, they use the summary info rather than click the link and go to the website for the information. Obviously, that reduces the website's "hit count." I'm a boomer, and I still click through. But in this case, I could not find the information on the websites! For the reddit link, I could not access the comments. For the Facebook link, I have no idea where Google found that information. But that was exactly the info that I was after.

Google search results
reddit link
Facebook link

Upstream has different fish species than the downstream has.

storymaps
"Boat propulsion is limited to rowing, paddling, or battery powered motors...The black bass population is the primary focus of sampling efforts and management. Electrofishing surveys are conducted to assess the population structure of black bass and other gamefish.  "

brayman
$6m project completed in Apr 2010.
"The Prettyboy Dam project involved the installation of an underwater anchorage system necessary to secure the concrete gatehouse to the dam."