FOSC Physical and Chemical Data

FOSC Chem/Bio WQ Monitoring Summaries
(data to be added)

February 2020

This is a brief summary of results of chemical and bacterial monitoring at various locations along Sligo Creek.

Wheaton Lane

Volume was moderate, slow and cold. Bottom again covered with thick layer of brown silt and algae. Lots of folks out walking and jogging, along with robins, a downy woodpecker and six whitetail deer. Not all in one group. Detergent level was highest ever here, but chlorine was about half last month’s levels, and other chemical indicators were near standard winter lows. Air quality was quite good and noise levels were slightly higher than usual.

Dennis Avenue

Volume was stronger than usual. Bottom a combo of sand and leaf litter. Chickadee, downy woodpecker and possibly a kingfisher spotted. No tracks seen. Side channel still slowly forming along eastern bank. A few joggers and walkers. All readings were low, except for surfactants, which remain higher than normal. Air quality and noise were very good here.

Flora Lane

Changes here – flow was fuller and slower, with dust or sediment sitting on surface. Also, lots of organic/mulch debris on substrate, which had been probably the cleanest stream bottom that we see. No fish, no birds. Salinity, TDS and conductivity were all about double Dennis Ave readings. Total dropped way down from last month, but detergents continue to increase – up to 5.1 ppm this month. Air quality was excellent, noise levels were slightly lower than usual.

Dallas Avenue

Volume was moderate and slow. Substrate a mix of sand and silt, pool a consistent 2 feet deep now. About a half dozen joggers and walkers. No fish, but mallard pair, robins, and snowdrops starting to bud nearby. pH was high at 8.68, detergents were also high near 5 ppm, and chlorine was particularly hot for this site; .26/.32 ppm, free and total, respectively. Noise and AQ were excellent.

Bennington Drive

Volume was moderate and clear, sharp contrast to last month’s massive sediment discharge. Leaf out beginning, and lots of avian friends heard or sighted, including redtail hawk, turkey vulture, crows and cardinals. Most chemistry indicators were normal winter levels, except detergents – high at 4.4 ppm – and total chlorine, also elevated at .58 ppm. Noise levels were average, and air quality very good.

Wayne Avenue

Volume was moderate. Channel shallower with sand and some rock debris. No fish. Surfactants almost double from last month to 5.5 ppm. Salinity, TDS and conductivity levels were about average for this site. Total chlorine levels were high (.26 ppm). Noise levels nudged up a bit to 58.4 dB. Air quality was very good.

Fleetwood Terrace

Volume was moderate, water clear. No fish seen, algae 2-4″ long. Robins seen, blue jay and pileated woodpecker heard. Bud break underway. The seep/slough water levels were moderate and semi-frozen. Surfactants were elevated for this site at 4.7 ppm. pH was unusually high again, this time at 8.78 (compared to last month’s 8.99). Salinity, TDS and conductivity levels were low for winter. Noise and AQ were both average for this site.

January 2020

This is a brief summary of results of chemical and bacterial monitoring at various locations along Sligo Creek.

Wheaton Lane

Volume was low and cold. Heavy brown silt across bottom, algae about 2″ long. Heard red-tail hawk call, saw deer tracks. A woman who often walks the trail says the water turns “black” during rainfalls, saying she thought it was from car oil or some other fluid. Man and his dog forded the stream and asked about the health of the stream. Readings were fairly low hear, except for chlorine, which was very high compared to the Creek’s mean, especially in winter. Surfactants were low, air quality and noise were very good.

Dennis Avenue

Volume was moderate, light silt and algae. No wildlife seen or heard. Plunge pool is deeper now, with side trib forming along bank. No families or kids in park this time, but a few joggers and walkers. All readings were quite low, except for chlorine and surfactants, which were middle of the range. Air quality and noise were very good here as well.

Flora Lane

Clear, deep, moderate flow here. No fish, no birds. Temperature, salinity, TDS and conductivity were all about double Dennis Ave readings. Total chlorine was high as well. Ammonia barely registered here, as opposed to the zeros at Wheaton and Dennis. Air quality very good, noise slightly higher here than other upstream sites because of Beltway proximity.

Dallas Avenue

Volume was moderate to low; slow current. Substrate clear with some leaf litter. Trib being restored, so pump removing water and shunting around sandbags and curtain, downstream to main channel. No wildlife, no fish, a few pedestrians walked by. Ammonia-N levels at 0, surfactants, salinity, TDS and conductivity levels all fairly low for winter. Perhaps lack of snow and subsequent lack of road salting? AQ was excellent.

Bennington Drive

Volume was heavy and completely turbid with tan-colored silt. Entire spillway, apron and pool opaque. A Water WatchDog event that we are following up on with WSSC and DEP. Ammonia-N levels up to 0.08, surfactants at 0 ppm, which is probably a first. Salinity, TDS and conductivity levels all quite high, and would probably have been higher if we’d taken our sample five minutes earlier. Chlorine levels moderate. Noise levels were moderate, air quality excellent.

Wayne Avenue

Purple Line construction has hit this site. Sandbags and box boulders right up to the outfall. Volume was low to moderate. Channel was shallow with sand and small asphalt pieces in pool and on apron. No fish. Small but steady line of suds from outfall. Ammonia-N levels were high for winter at 0.18 ppm, surfactants at 2.9 ppm. Salinity, TDS and conductivity levels were all seasonally appropriate, i.e., higher than average. Chlorine levels were very high (.14/.26). Noise levels were about 56 dB (a little low here), and air quality was very good.

Fleetwood Terrace

Volume was low to moderate, water clear. No fish seen, algae 2-4″ long. Kingfisher and red-bellied woodpecker seen, blue jay heard. Deer tracks present. The seep water levels were low but steady, surprising given the lack of rain lately. Ammonia-N levels at 0.02, surfactants were up at 3.9 ppm. pH was unusually high at 8.99. Salinity, TDS and conductivity levels were low for winter. Noise levels nudged up a bit to 55 dB. Air quality good here, though slightly poorer than most other sites this day.

May 2019

This is a brief summary of results of chemical and bacterial monitoring at various locations along Sligo Creek.

Wheaton Lane
Flow volume was low. Two small fish seen, few birds heard. Substrate is lightly covered in algae. Ammonia-N level moderate at 0.15 mg/L. pH was more basic than usual – almost 9 – but temp was seasonally appropriate. Salinity/TDS/conductivity were low, and chlorine was at 0. Surfactants at 2.8 ppm, about their usual range here. Noise level above normal at 63 dB, but this was because it was mowing day at Parks, apparently.

Dennis Avenue
Volume was moderate to low here. Ammonia-N level at 0.08. Surfactants were about 1.8 mg/L. Chlorine levels lower were .03/.09/.06. Salinity/TDS/conductivity were about 10% higher than Wheaton. We saw about 15 juvenile fish. Substrate fairly clean, with little algae or silt. Noise levels around 61.5 dB, which is high, again because of mowing decks in the area.

Flora Lane
Moderate water flow this time, and substrate was cleaner than usual (no algae, mostly sand). Ammonia-N was 0.11, surfactants were 1.8 ppm. Free and total chlorine were .03 and .10, respectively. Conductivity, TDS and salinity were about double Wheaton and Dennis readings. About 15 juvenile fish spotted. Lots of bird and mosquito activity. Noise around 56 dB.

Dallas Avenue
Volume was low. Substrate clear. No tracks seen, but gnats and juvenile water striders in abundance, and a couple released a box turtle near the bridge (it had crawled up near their swimming pool). Ammonia-N levels at 0.9, surfactants were up at 2.8 ppm. Salinity, TDS and conductivity levels between Wheaton and Dennis readings. Chlorine levels low this time around. Noise levels were about 56 dB. Construction crew (Sligo pathway and foot bridges) nearby, with lots of walkers and bikers in the area.

Bennington Drive
Volume was moderate. Apron and pool relatively clean, though pool column somewhat cloudy. Ammonia-N levels at 0.42, which is pretty high. Surfactants at 1.9 ppm. Salinity, TDS and conductivity levels were all quite high, close to winter territory. Chlorine levels were a bit high (0.14 ppm for total chlorine). No snails, unusual for this late in the spring, but raccoon tracks seen in the apron’s silt. Noise levels were about 51.5 dB.

Wayne Avenue
Volume was high, channel outfall pool was deep. Lots of orange iron floc on the outfall pipe. About 30 fish, mostly juveniles and fry, as well as lots of birds. Ammonia-N levels at 0.16, surfactants at 2.1 ppm. Salinity, TDS and conductivity levels were all high, similar to Bennington Drive’s numbers. Chlorine levels were all fairly low. Noise levels were about 59 dB (normal here).

Fleetwood Terrace
Volume was moderate, water clear. No fish seen, very little algae. Several dragonfly pairs near the seep/slough, where water levels were high and consistent flow through to the main channel appears now to be well-established. Ammonia-N levels at 0.09 ppm, surfactants steady here at 1.8 ppm. Salinity, TDS and conductivity levels were midrange, along the lines of Dallas Avenue. Chlorine levels were quite low, and noise levels were at 55.5 dB.

Maple Avenue
Volume was heavy, covering the entire remaining outfall spillway. Steady flow of sandy sediment from 01A and, to a lesser extent, 01B, through monitoring. 01B has very heavy iron floc throughout, and 01C also has steady flow (which appears to be the new normal for this pipe). Receiving pool was completely opaque with suspended sediment – could not see the bottom. Ammonia-N levels were 0.13 and 0.38, 01A/01B respectively. Surfactants were 2.7 and 0.6 ppm in 01A and 01B. Salinity, TDS and conductivity levels were moderately high and quite similar to one another. Chlorine levels were low in both pipes. Raccoon tracks in apron sediment/algae layer. Noise levels were about 57.3 dB.

April 2018

This is a brief summary of results of chemical and bacterial monitoring at various locations along Sligo Creek.

Bennington Drive
Volume was heavier than usual in SA10. Some dead terrestrial worms on the apron and in the pool, which was very cloudy with suspended sediment. No snails. Lots of convenience store trash (plastic coffee cups, ketchup packets, etc.) this time. Musty, detergent scent occasionally came down the pipe. Apron has a gray algae carpet, outfall now has orange and bright green algae. Birds everywhere. Ammonia-N level low — 0.11 mg/L. pH and temp seasonally appropriate, salinity/TDS/conductivity all near winter highs again. Chlorine levels were low, but surfactants went back up to 4.0 ppm – pretty high. Air quality readings and noise level both very good. Coliform readings dropped moderately from last readings.

Wayne Avenue
Ammonia-N down to a low (for here) 0.29 mg/L, or 1/4 February’s reading. Coliform numbers, however, were much hotter at TNTC. No positive correlation here. pH was a bit lower than usual, and salinity/TDS readings were on the downward spring slope, though still a bit high. Surfactants were down – 2.7 ppm. Steady light suds from outfall pipe and in main channel. Receiving pool was clear with a sandy bottom this time. Birds loud and common, including a pileated woodpecker(?). The fish posse is back – about 20 adults and approx. 100 fry and juveniles.

Fleetwood Terrace
Surfactants were down from February to 1.5 ppm – much improved from winter’s reading of 5.7ppm. Free and total chlorine eased down a bit, ammonia-N held steady at 0.13 mg/L. pH came in at 8 this time, much higher than the sub-4 we saw here last time. Conductivity, TDS and salinity were all low, as was chlorine. Total Coliform levels almost doubled, but E.Coli was almost 50% lower. Gray rock algae 2 to 6 inches long, about 15 fry swimming near sample site. Strong flow in channel. Heard and saw redtail hawks. PM readings snuck up a bit though still excellent, same for dB, now at 55. The Hartford seep is filling with sediment, but also appears to be establishing at least an intermittent flow connection with the Creek now.

Maple Avenue
Flow volume strong in 01A and 01B, as well as 01C, which is apparently no longer unusual. Occasional soap/detergent smell across apron. Ammonia-N levels headed were mixed, both around .15 mg/L. Salinity, TDS and conductivity levels were about average, though 01B is higher on all parameters, including pH (almost 8). Water level in pool was high, quite cloudy from suspended sediment. Delta is only about 2 inches below surface now because of sediment accumulation. Apron now features a highback office chair and more plastic trash than usual. Chlorine levels were lower (0.02 to 0.04 range). Birds common, including robins, blue jays, crows and sparrows. A LOT of trash in stream and along banks. PM AQ levels were excellent, noise levels crept up a bit to 58 dBA.

February 2018

This is a brief summary of results of chemical and bacterial monitoring at various locations along Sligo Creek.

Bennington Drive
Volume was a bit heavier than usual in SA10. Lots of dead terrestrial worms on the apron and in the pool, as well as a fine layer of gray silt. Iron algae was stronger than usual in SA11. Ammonia-N around usual level here — 0.29 mg/L. Temperature and pH were seasonally appropriate, while salinity/TDS/conductivity all near winter highs. Total chlorine was back up to .26 ppm from 0 last month and surfactants continue to drop, though still high. Air quality and noise levels were both good, though a little louder than usual. Coliform was a mixed bag, with E.coli slight lower, but Total coliform rose somewhat, both at levels higher than we’d like to see. AQ excellent, noise at 44 dB.

Wayne Avenue

Ammonia-N shot way up here this time — 1.04 mg/L, or 4 times last month’s reading. This tracks with Coliform numbers which, as usual, are very hot. Surfactants were way down – about 60% drop – which is good news, despite a steady, moderate flow of surface suds during our visit. Receiving pool has more silt than during our last visit, shallowing it up. Lots of crows and cardinals nearby, as well as raccoon tracks, and the outfall fish are back – about 15, mostly adults, including several almost a foot long. Where they go during the winter remains a mystery. AQ excellent, noise at 58 dBA.

Fleetwood Terrace
Surfactants were high (4 ppm), though down from last reading of 5.7ppm. Free and total chlorine were elevated from norms (.10 and .07 ppm, respectively). Ammonia-N was at 0.13 mg/L, which is a bit high for the open channel. pH appeared quite low at 3.52, so we’ll need to follow up next week to see if this accurate. Coliform levels held steady at higher-than-we’d-like range. The beaver dam has been removed. Snowdrops were in full bloom with some crocus mixed in. Suds seen downstream of monitoring site; there were likely from riffles as upstream run section did not have them. AQ excellent, noise at 50 dB.

Maple Avenue

Flow volume strong in 01A and 01B, as well as 01C, which is unusual. Ammonia-N levels headed up to 0.08 and 0.24 mg/L, respectively. Water level in pool was high, somewhat cloudy, though there was no evidence of recent surfactant discharge. Chlorine levels were back to fairly standard levels (0.03 to 0.11 range), well down from December’s astronomical 3.61 free chorine/5.01 total chlorine in KE01B. Surfactants levels were substantially lower as well. Two duck pairs present when we arrived – mallard and wood duck. A LOT of trash in stream and along banks. AQ excellent, noise at 54 dB.

December 2017

This is a brief summary of results of chemical and bacterial monitoring at various locations along Sligo Creek.

Bennington Drive

Salinity/TDS/conductivity all remain near their standard winter highs. Chlorine levels and ammonia-N were zero, which is unusual and welcome. Detergent levels, however, were high (4.7 ppm LAS), though down from last month’s 6.1. Sound levels were low (40 dB) and air readings were good, but Coliform levels more than tripled from November’s readings. No snails, but many birds present. Gray silt in receiving pool now; last month was clean and sandy.

Wayne Avenue

Ammonia-N here was half of last month’s high reading. Salinity, pH and TDS were all slightly below winter averages. Chlorine was low, but detergent level was quite high again (5.6 ppm LAS). Ice surrounded the outfall’s surface waters, including a patch of brownish yellow foam frozen into it. Coliform levels were again extremely high. No fish or birds.

Fleetwood Terrace (main channel)

Water temperature (0.1 C) was noticeably lower than at outfalls. Brrr. Detergents were high at 5.7ppm. Free and total chlorine were elevated (.10 and .07 ppm, respectively). Coliform levels ticked back up to the 1000/2000 ECU level. No aquatic life visible, but a beaver dam is well under way and water level upstream is rising.

Maple Avenue

Flow volume moderately strong in 01A and 01B, no flow in 01C. Ammonia-N levels way down to 0.04 and 0.01 mg/L, respectively. Salinity, TDS and conductivity levels were low, but pH was high (+8). Chlorine levels in KE01A were high, but nothing compared to KE01B (3.61 free chorine, 5.01 total chlorine). These levels are higher than commonly found in swimming pools and hot tubs. Surfactants levels were high in both outfalls as well.

Summary

On the chemical readings, surfactants (soaps/detergents) everywhere appear to remain persistently high. Sediment was not the pressing issue this time around that it has been for much of the fall. On the biological side, as always, Wayne Avenue produces the highest Coliform readings, and we generally saw some increases in Coliform readings, except at Maple Avenue (the chlorine blast being a part of that).

November 2017

This is a brief summary of results of chemical and bacterial monitoring at various locations along Sligo Creek.

Bennington Drive

Volume was moderate at SA 10 with few suds. Salinity/TDS/conductivity were all slightly higher than usual for this time of year. Occasional small suds in current. Chlorine levels were back up, as was ammonia-N (0.26 mg/L). Surfactants level was very high (6.1 ppm), sound levels were down from prior readings (to 43 dB) and air readings were quite clean as usual. Coliform levels were down substantially from October’s reading, but E. Coli tripled. Our snails appear to be gone for the season. Outfall had maroon algae, which i common here. Bird activity was high. Almost no silt or dirt in receiving pool – unusually clean, sandy bottom.

Wayne Avenue

Ammonia-N edged up to the 0.50 mg/L mark. Salinity, pH and TDS were all slightly below fall averages. Chlorine quite elevated (.08 ppm total chlorine), surfactants also extraordinarily high (6.3 ppm LAS). Steady stream of suds down main channel was clearly visible. Light tan algae on outfall’s final 2 feet. Coliform levels extremely high – TNTC (too numerous to count) About 20 fish, all 4 to 8 inches long above leaf litter of receiving pool. Moderate flow in channel. AQ readings slightly higher (worse) than at Bennington, but still within the safe/excellent range. Noise level averaged about 57 dB. No birds seen.

Fleetwood Terrace (main channel)

Temperature was noticeably lower than at outfalls. Surfactants were much higher than usual here as well (3.9 ppm). Free and total chlorine were lower than recent readings (.01 and .02 ppm, respectively). Ammonia-N ticked down to 0.14 mg/L and conductivity, TDS and salinity all remain fairly low. Coliform levels have dropped substantially from mid-summer readings (now 600EC/1500TC). No aquatic life visible, but a great blue heron appears to have made the newly-built seep one of its hunting grounds. Algae covering the rocky substrate, still about 3 to 9 inches long. Moderate flow in channel, currently impeded by a branch and leaf dam that has raised the water level behind it by about 4 inches. PM readings excellent, dB again at 52.5.

Maple Avenue

Pool appeared to have received small detergent discharge just before arrival. Then a 30-minute slug of sediment from 01A outfall began during monitoring. Steady stream of suspended, light tan sediment that clouded the pool brown and filled half the receiving apron. This same light tan colored sediment is clearly visible all across the apron, suggesting this is not an isolated incident. Flow volume moderately strong in 01A and 01B, no flow in 01C. Ammonia-N levels were about double October’s (0.14 and 0.34 mg/L, respectively). Salinity, TDS and conductivity levels were low. Water level in pool was moderate, outfall apron cracks have grown and it continues to tip into the receiving pool. Chlorine levels in KE01A were quite low, but sky high in KE01B (.07 free chorine, .30 total chlorine). Surfactants were high in both outfalls as well, particularly KE01A (3.7ppm). Raccoon tracks in iron algae of KE01A only. A fair amount of plastic trash, leaf dam in 01B. PM AQ levels were excellent, noise levels at about 57 dB, which is normal here.

Park Ritchie

No report made.

Summary

On the chemical readings, surfactants (soaps/detergents) everywhere and sediment at Maple Avenue are the big surprises. On the biological side, as always, Wayne Avenue produces the highest Coliform readings, and we also saw a big spike in the KE01A numbers at Maple Ave in TKPK. Bennington was a mixed bag and Fleetwood’s numbers were a step in the right direction. Please let me know if you have any questions about this month’s chemical or Coliform readings. As always, I will share this with Steve Martin at DEP as well.

September 2017

This is a brief summary of results of chemical and bacterial monitoring at various locations along Sligo Creek.

Bennington Drive

Ammonia-N level was normal for this location. Volume was high from SA 10 with very few suds. pH and temperature as well as salinity/TDS/conductivity were all slightly higher than usual for this time of year. Chlorine levels were quite low, as was ammonia-N (0.11 mg/L). Surfactants were almost half of what they were last time out, sound levels were normal (50 dB) and air readings were extraordinarily clean. Coliform levels down substantially from late June’s reading but are still elevated. May have startled a frog into the receiving pool but can’t be sure. There were about a hundred snails clustered around the SA10 outfall and bird activity was high. An apparently thick layer of silt or dirt or dead algae covered the bottom of the receiving pool. Maroon color on outfall pipe stone.

Wayne Avenue

Ammonia-N remains near the 0.40 mg/L mark. Salinity, pH and TDS all slightly below fall averages. Chlorine slightly elevated, surfactants on the rather high side (3.4ppm LAS). Light brown algae on outfall’s final 2 feet. Coliform levels quite high as usual, but 30% to 50% lower than the summer readings. About 100 fish gathered in radial lines centered on the outfall, everything from fingerlings to adults. Approx. 80% blacknose dace, 20% white suckers. Deep, wide flow in channel. PM readings excellent, dB at about 57, per usual.

Fleetwood Terrace (main channel)

Surfactants were lower (1.1 ppm) than usual. Free and total chlorine are still noticeable (.02 and .04 ppm, respectively). Ammonia-N ticked up slightly to 0.22 mg/L but conductivity, TDS and salinity all remain near the summer lows. Coliform levels high (around 2K), but much less than mid-summer readings. About 2 dozen fish fry present, as well as snails on sandy bottom, tucked just downstream of trailing rock edges. Algae covering the rocky substrate, but it is shorter now, e.g., 3 to 12 inches, than at the height of summer. Deep, wide flow in channel. PM readings excellent again, dB at 52.5.

Maple Avenue

Pool received small detergent discharge just before arrived, then 20-minute slug while we monitored. Trickle of suds came first from 01B, then a move obvious stream came from 01A. Shampoo or detergent scent in the air several times. Flow moderate to strong, including 01C. Ammonia-N levels were low (0.7 and 0.20 mg/L). Salinity, TDS and conductivity levels were low. Water level in pool was high, delta about 12 inches beneath water surface, outfall apron has cracked and begun to slide into receiving pool. Chlorine levels were high (.05 and .04 ppm) in KE01A, while surfactants were high in KE01B at 3.5ppm LAS. Copious raccoon tracks in iron algae of KE01A only. Some plastic trash on apron and stream banks. PM2.5 and PM10 AQ levels were 50% to 100% higher than at other sites, but noise levels were at about 53 dB, which is lower than usual.

Park Ritchie

No report made.

Summary

Our September chemical and Coliform data generally indicate that the Creek’s situation is neither noticeably worsening nor improving compared to previous Septembers. We still see the chronic detergent discharges directly into the Creek from storm water drains along Maple Avenue in Takoma Park, as well as remarkably high levels of Coliform bacteria being discharged from the Wayne Avenue storm water pipe near SSIMS. For at least the past year, we have also seen elevated levels of sediment entering the Sligo Creek system via the Bennington Road tributary, and we continue to see surprisingly high Coliform and chlorine numbers in the main channel. On the positive side, ammonia-N readings are generally flat or down slightly from last year, air quality readings have been excellent, we see somewhat less trash near the pipes and tributary outfalls, and the number of fish and snails present appears to be increasing slightly.

June 2017

This is a brief summary of results of chemical and bacterial monitoring at various locations along Sligo Creek.

Bennington Drive

Last time out (end of April) we had the huge volume with suds and extraordinarily high chlorine readings. This time around, the outfalls were far less dramatic. Ammonia-N levels were average (0.11 and 0.12 mg/L), but salinity, temperature and TDS were all somewhat elevated in SA10. Chlorine levels were back down to their usual range. Surfactant levels were lower than last month, but still in the 3 ppm LAS range. As detailed below, Coliform levels were very high coming from SA10. Receiving pool was somewhat turbid, sediment lessened and water level high, so pool effectively as deep as we’ve seen here. Layer of silt over layer of algae on apron. Flow medium/low respectively (SA10/SA11). PM air quality was excellent, noise level at 49 dB. The snails are back, lots of birds heard, plus mosquitoes. Iron algae absent from SA11; unusual for this time of year.

Wayne Avenue

Ammonia-N remains near the 0.40 mg/L mark. Salinity, pH and TDS all slightly above summer averages. Chlorine at zero, but surfactants were elevated (2.9ppm LAS). Light brown algae on outfall’s final 2 feet. Coliform levels quite high as per usual. About 60 fingerling and juvenile fish, 80% blacknose dace, 20% white suckers. Fewer suds than usual in pipe and main channel, but more trash along banks. Deep, wide flow in channel. Birds everywhere. PM readings excellent, dB at 57.

Fleetwood Terrace (main channel)

Numbers here were pretty standard for the main channel, except surfactants were lower (1.9 ppm) than usual. Free and total chlorine are still noticeable (.03 and .05 ppm). Ammonia-N came in at 0.17 mg/L and conductivity, TDS and salinity all near the summer lows. Coliform levels high (3K to 7K), especially given expected dilution in main channel. About a dozen small fish fry present. Algae covering the rocky substrate, some 2 to 3 feet long. Deep, wide flow in channel so that tree root collars are wet on both sides. PM readings excellent, dB at 53.

Maple Avenue

Pool received small detergent discharge just after we arrived. Laundry detergent scent from 01A easily detected. Flow strong, including 01C. Ammonia-N levels were about half of last month’s, lower than average as well. Salinity, TDS and conductivity levels were low. Water level in pool was high, delta about 6 inches beneath water surface. Chlorine levels, however, were quite high (.09 to .34 ppm) and surfactants were between 1.0 and 2.1ppm. Copious raccoon tracks in iron algae of 01B. Some birds downstream. PM AQ levels excellent, noise levels at about 57 dB.

Park Ritchie

The pool here was as small as we’ve encountered, surrounded by mud filled with deer tracks. Mulch odor was apparent. All levels were extremely high, due to the concentration of pollutants into smaller volume of water. In particular, ammonia-N came in at 1.82 mg/L, chlorine was in the .75 ppm range, and surfactants registered a 6.1 ppm LAS. AQ excellent and noise dB at about 50.

April 2017

This is a brief summary of results of chemical and bacterial monitoring at various locations along Sligo Creek.

In Silver Spring at Bennington Drive Dramatic change to outfall during my monitoring visit. Flow went from moderate volume and clear, to the fastest flow rate I’ve seen here, filled with detergent suds and smelling of chlorine. This large discharge lasted at least 40 minutes. Reported 3 times via WWDogs. Ammonia-N levels were average (0.12 and 0.17 mg/L) but these samples were taken before the slug began (same for salinity, temperature and TDS). Total and available chlorine levels were huge – 20 to 50 times average readings here. Surfactant level was also high (4 ppm LAS), though we’ve seen greater values at other outfalls in the past. Receiving pool clear but shallow because of sediment filling up the bottom. Layer of silt over layer of algae on apron. PM air quality was good. Robins and cardinals everywhere, raccoon tracks, but no snails, frogs, etc.

Ammonia-N levels at Wayne Avenue is back to its normal – around 0.40 mg/L. Salinity, pH and TDS all holding steady at typical spring levels. Chlorine quite low, but surfactants were elevated (2.3ppm LAS). Gray algae on outfall’s final 2 feet. About 70 fingerling and juvenile fish, 80% blacknose dace, 20% white suckers. Birds galore.

Downstream, the Fleetwood Terrace numbers were pretty standard for the main channel, except surfactants were higher (2.7ppm) than usual. This could have been a result of this site being about 200 meters downstream from Bennington Tributary. Free and total chlorine were a bit high, especially given the volume and dilution we’d expect to see in the main channel. Ammonia-N came in at 0.15 mg/L and conductivity, TDS and salinity all near the summer lows. No fish present, but lots of birds heard.

In Takoma Park, the Maple Avenue pool appeared to have just received a detergent discharge – cloudy green color, old suds floating on top. Detergent/hair care scent from 01A easily detected, with hint of cigar/cigarette smoke as well. 01B was mostly cigar/cigarette scent. Flow strong this time in all outfalls, including 01C strongest trickle I’ve seen there. Ammonia-N levels were 01A at 0.20 and 01B at 0.27 mg/L, which is about average here. Salinity, TDS and conductivity levels holding steady around average, chlorine levels and surfactants were highest at 01B – around 2.1ppm. Little algae, no fish, mammal tracks, some birds downstream. PM air qual levels good here as with other sites today. Noise levels average at around 53dB.

No report for Park Ritchie this month, Pat ran out of time.

February 2017

This is a brief summary of results of chemical and bacterial monitoring at various locations along Sligo Creek.

In Silver Spring at Bennington Drive storm water outfalls, salinity and conductivity levels all declined slightly, while the chlorine levels nudged up a bit. The water from both pipes contained more ammonia-N (which is often an indicator of biological matter or waste in the water) than December’s reading. Coliform levels more than tripled at the left pipe (facing up stream), and also rose slightly in the right pipe. and detergent levels both pipes remain high, though slightly lower than our last readings.

Ammonia-N levels at Wayne Avenue’s fell by almost 85% from December’s remarkably high levels (1.14 mg/L). Conductivity, TDS and salinity all held steady, surfactants declined somewhat but remain very high, and chlorine edged up slightly. Coliform levels declined to “only” 30,000 cfus/100mL from the usual “too numerous too count” level. Wayne Avenue’s outfall pipe is consistently quite high for E. Coli and Total Coliform ¬ – far above recommended skin contact levels.

Downstream, the Fleetwood Terrace location – in the middle of the Sligo Creek channel near the parking lot on Sligo Creek Parkway between Wayne Avenue and Piney Branch Road – also saw high levels of Coliform in the water (three to six times December’s readings). Chlorine levels quadrupled and surfactants (essentially, detergents, cleaners, soap) remained stable but high. Most of the rocks on the bottom of the stream in this stretch are now covered with a long, dark gray algae.

In Takoma Park, the Maple Avenue storm water outfalls continue to see visible pollutant discharges of detergents. Ammonia-N levels were low in the left pipe, but almost tripled in the right pipe to 0.29 mg/L. The right pipe also saw a ten-fold increase in its Coliform levels as compared to December’s readings. Conductivity, TDS and salinity readings essentially held steady near recent lows.

The CSO overflow pools behind the Park Ritchie apartments had their lowest water levels that we have seen. All pollutants rose when compared to December’s readings, in some cases by five to ten times. In particular, the southwest pool had a chlorine reading of 0.5 ppm, more than ten times its prior level. These high levels are not unexpected because of the lack of rain and concentration of pollutants in a small bodies of standing water. Coliform levels were lower than normal. Because of the Coliform levels we are finding at our flowing monitoring sites, we would not recommend that you or your pets enter the Creek near these outfalls or the main channel near Fleetwood Terrace at this time or, if you do, we recommend that you wash thoroughly with soap and water after any contact.

Monitoring water quality with the new colorimeter

Above: Water quality team monitoring near Wayne Avenue outfall

Above: Gathering Creek water quality samples near Dallas Avenue

FOSC Chem/Bio WQ Monitoring Data Sheets

(more data sheets to be added)

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Wheaton Lane testing site

Wheaton Lane testing site

Dallas Ave testing site

Dallas Ave testing site

Bennington Drive testing site

Bennington Drive testing site

Fleetwood Terrace testing site

Fleetwood Terrace testing site

Dennis Ave testing site

Dennis Ave testing site

Flora Lane Testing Site

Flora Lane testing site

Wayne Avenue testing site

Wayne Avenue testing site

Maple Avenue testing site

Maple Avenue testing site

Park Ritchie testing site

Park Ritchie testing site