Tales of Stream Monitoring Fun
Lake Accotink Park
Friends of Lake Accotink Park
Friends of Accotink Creek

Friends of Accotink Creek and Friends of Lake Accotink Park hold biological stream monitoring workdays four times per year.
Thanks to all the volunteers who have joined us for this important data-collecting activity!

December 10, 2016 Stream Monitoring:

Nippy temperatures never quite rising to the freezing point were made bearable for the bundled-up volunteers by cloudless skys and bright sunshine. As well as bundling up, our volunteers came unusually well-prepared for stream work, most wearing boots and waders.

It was not so bearable for our unfortunate collection of invertebrates. Instead of their usual wriggling and creeping about the net, they became immobile "bugsicles" encrusted with ice when exposed to the below-freezing air. Most seemed to be somewhat restored once they were plucked from the net and placed in the water of the collection trays.

We needed only one net to collect 352 invertebrates, well above the minimum 200. As usual, however, the collection was poor in variety of species, being dominated by netspinners and aquatic worms. Accotink Creek received a disappointingly low numeric health score of 3 on a scale of 12, well into the unacceptable range. See the tabulated results here.

The smothering sediment of streambank erosion from stormwater runoff is the principle cause of the poor health of our creek. Learn about how you and your community can receive financial assistance to "become the change" through Conservation Assistance.

Our September 10, 2016 Stream monitoring:

The long dry summer perhaps breathed its last today, as warm sunny weather prevailed ahead of predicted cooling tomorrow. Yet it has not been quite so dry that we did not have good water flow conditions for monitoring.

Twenty-one assorted volunteers gathered to check the health of Accotink Creek today. The members of Brownie Troop 783 were among our group, after having been resourceful enough to correct the mistaken date information we had supplied to them.

Enroute to the creek, we were pleased as "punch" to see a section of puncheon boardwalk had been installed over a muddy spot in the trail by unknown benefactors. Puncheon is a style of boardwalk with boards arranged lengthwise, and usually laid right on the ground. It is a much gentler alternative to the asphalt of the adjacent Cross County Trail. We hope this good work is not doomed to be washed away when the next heavy rainstorm sends Accotink Creek over its banks.

At first glance, our initial net appeared nearly devoid of invertebrates, so we put in a second net right away. We needn't have bothered, though, for sharp-eyed volunteers found more than the minimum required number of 200 invertebrates in the first net alone.

We were happy to see a hellgrammite among our finds today, a creature we've not seen for the past two years. It's increasing rarity cannot be a good sign for creek health.

After our appallingly low score of 1 last June, we were somewhat gratified by a score of 5 today, on the 0 to 12 scale, right in the usual range of mediocre stream health we are accustomed to. It was likely only by chance we did not capture a single lung snail or Asiatic clam today, whose absence helped nudge the score upward. See the tabulated results here.

Our June 4, 2016, Stream Monitoring:

Thunk! Like a stone dropped in the lake, the numeric stream health score of Accotink Creek sank from its usual mediocre 4 to an abysmal 1!! Let's hope this is a mere anomaly and not a portent.

Under overcast, warm, and humid conditions, the volunteers found slim pickings in the streambed and had to set out four nets to catch the minimum number of 200 invertebrates. At a glance, the mix of invertebrate species appeared to differ little from our usual catches. Yet, once the numbers were plugged into the standard formula, we were stuck with a disappointing 1 on a scale of 0 to 12. See the tabulated results here.

We did have some unusual catches today - two ramshorn snails, a gilled snail, one adult beetle, and two beetle larvae.

Our May 7, 2016 Creek Critters survey:

The week-long spell of rainy skies ended just in time for our Creek Critters outing, giving us an ideal day of mostly sunny skies and mild temperatures. Girl Scout Troop 4339 turned out in numbers to join us.

Our monitoring site today was adjacent to the USGS stream gauge in Wakefield Park, just upstream from Braddock Road. Walking to the site, volunteers enjoyed a view of the nearly completed stream restoration project on an unnamed tributary. A discussion followed of the motives and merits of such projects, which aim to curb the excessive erosion of our streams caused by stormwater runoff from paved surfaces.

Accotink Creek was still running rather high after overnight rain, so we were unable to access the best spots for sampling, the shallow riffles where oxygen-rich waters support the most invertebrates. Even though we were confined to the margins of the creek, our volunteers still managed to find an interesting sampling of invertebrates, including rare finds for our creek such as aquatic beetles and sow bugs and abundant mayflies.

The Creek Critters smartphone app walks users through the use of stream monitoring kits, invertebrate identification, and reporting results in simple steps. As usual, Accotink Creek scored in the "poor" water quality range, confirming our usual results with more traditional monitoring.

Monitoring leaders from Audubon Naturalist Society (producers of Creek Critters ) and Prince William Soil and Water Conservation District reminded all of the opportunities where they live, work, and worship to contribute to preserving healthy waters for future generations.

Our March 12, 2016, stream monitoring:

A dozen volunteers gathered under gray skies, an omen of the uninspiring results we would have today. At least we enjoyed mild temperatures and dry weather.

The invertebrates were few and far between today. We required three nets to reach the minimum count of 200 invertebrates. Our haul was overwhelmingly dominated by aquatic worms, most of them quite small. We also found a good number of midges, our second most abundant species of the day. Other than worms and midges, we collected only a handful of other individual specimens of netspinners and leeches.

As ever, Accotink Creek scored an unacceptably poor stream health score of 4 on a scale of 12, far from breaking the barrier of 7 to be considered in the healthy range.

Mussel Rescue February 26 - 29, 2016:

Winter thunderstorms sent the USGS stream gauge on Accotink Creek at Braddock Road above 2000 cubic feet per second late at night on February 24th. This flow rate is enough to push freshwater mussels out of the creek and leave them stranded on the banks and gravel bars. As the high water receded over the next few days, we searched the creek banks for stranded mussels.

We found 23 stranded mussels and returned them to the creek. Freshwater mussels are found only in a remnant population in a short stretch of Accotink Creek just downstream from the dam.

See the rest of the mussel rescue photos here.

Read about our 2015 freshwater mussel biological survey.

Learn more about freshwater mussels.