Aerial and Field SAV Observations

Aerial and Field SAV Observations header image 2

Shallow Creek, mouth of Patapsco, 8-24-11

August 29th, 2011 by Peter Bergstrom · No Comments

The day after the earthquake was a good day to survey SAV in Shallow Creek with near-perfect weather and fairly low tides. The water could have been clearer (Secchi was 0.45 m) but it’s usually murky here, and the salinity was 8 ppt.  This graph compares those values to what we measured here in past years; clarity this year was slightly below the long-term mean (0.52 m) while salinity was slightly above it (7.6 ppt). I paddled with Howard Weinberg, a GIS specialist who works for UMCES at the Chesapeake Bay Program, who helped with the planting here in 2000 and had not been back since.

I supervised small-scale SAV planting events here in 1999, 2000, and 2001, and helped with a MD DNR-led planting event in the same area in 2003. I try to check the beds every year since they have done so well. (For example, see my report from 2009 here, the year with the most extensive SAV cover.) We planted about half wild celery (Va) and the rest was redhead grass (Ppf) and sago pondweed (Ppc), but none of the Ppc seemed to survive, although the creek has some now. We found one small naturally occurring bed of Va in the outer cove before we planted in 1999, but genetic testing by Mike Lloyd and others showed that its genetics differed from the Va in the area we planted, showing that much of the Va in the creek is from what we planted rather than what was already there. We found no Ppf in the creek before we planted it there, so we assume that the Ppf there now is from what we planted, although its seeds can of course be moved by waterfowl.

The survey map from our visit has numbered areas (1-8) that I’ll refer to below. All the marked waypoints had some SAV. The same map and almost 70 photos of the SAV we found are in this web album (with captions) from the trip. The album includes the VIMS SAV maps of the creek (made for me by Dave Wilcox, thanks) from 2008-2010, which show that 2009 had the peak SAV area. Dave also calculated the mapped SAV area adjacent to where we planted in area 1, out to the channel and from the RR causeway up the creek to the launch point, and this graph of SAV area by year in that area showed that it peaked at almost 9 ha in 2009, after starting from the roughly 0.02 ha that we planted, but of course some of that 2009 area was milfoil (Ms) that we did not plant.

1. This shore was the main planting area in 1999 & 2000 and the only planting area in 2001 & 2003. We found similar SAV to what we found here last year: clumps of Ppf in the shallows (see photo, almost up to the edge of the marsh plants) changing to solid beds of Va (see photo) almost out the the channel, with some areas with mixed species. We also found slender pondweed (Ppu, see photo) at one spot in the shallows with Ppf, and also some Ppc (see photo showing its characteristic clumping of leaves) in a few other spots in the shallows.

2. The outer cove had beds of Va & Ppc in its mouth, and species diversity and density increased as we moved up the cove. First we checked the area where we planted SAV in 2000, at waypoints 353 & 354, on the south side of the cove. We found The Va and Ppf that we planted plus Ppc and quite a bit of curly pondweed (Pcr, see photo), a low-salinity species that is usually rare in this creek, probably more common this year due to the big spring freshet. As we moved up the cove the species diversity increased as common elodea (Ec) appeared, and at one spot (355) we found 6 of the 7 species that we found all day in one spot, all but Ppf: Va, Ms, Pcr, Ppc, quite a bit of Ppu, and a fairly deep carpet of Ec (see photo; Ec rarely grows to the surface in my experience but it can be quite dense). We did not have time to explore to the upper end but it appeared to have SAV all the way up. We left via the north shore of the cove, where there had been some Va before we started planting it (so we did not plant any there), and there is still a dense bed of Va with a bit of Ms at that same spot (see photo; waypoint 362).

3. SAV has spread in the shallows just outside the mouth of the creek into this area (349-351); extent seemed to similar to what was mapped recently. Va, Ppc, and Ppf were present but mostly Va. The Va here had more filamentous algae than most of the beds in the creek (see photo).

4. There is an old railroad bed that used to bring trains across the creek to the beach at what is now North Point State Park, that forms the southern edge of this cove (the outer cove is outside the RR bed).  This area had less SAV today than it had in recent years when it was completely full of SAV; this year there was a line near the mouth of the creek where the dense SAV ended, which we roughly followed as we paddled (see photo). The cove contained Va and Ms with less Ppf and Ppc.

5. The next cove up the creek had only Va and Ms, and also had a line across its mouth where the SAV appeared to end, also showing less SAV than last year.

6. The SAV started even a bit farther up this cove, and was also limited to Ms and Va, mostly Ms after we crossed the outer edge, with some Ppc. See a photo of one of the Ms beds here.

6a. The last cove on the right had Va with some Ms and Pcr, but the beds were patchy, much less extensive than last year.

7. After crossing to the western shore of the upper creek we found a bit more wild celery (Va), mixed with Ms, as the wind picked up (see photo of one of the beds). Both were generally shallow, and SAV was less extensive than in 2009-2010 (but more than what was mapped in 2008). A flock of Canada geese had been feeding in this area before we paddled over to it. I last saw a mute swan in this creek in 2009, and I used to see flocks of 6 or more here in the past (usually in area 4), which is good news for the SAV here.

8. This peninsula is where several watermen live on this creek, and the dredging of the channel on its north side  by USACE in about 1998 was what led to the funding for SAV planting here, as compensation for disturbing some milfoil (Ms) that was in the channel. Today there was a very shallow patch of Ms next to that channel at 396, and clumps of Va & Ms with Ppu at one spot along the point at the end of the peninsula (we also found Ppu in areas 1 & 2).

Launch–I checked for SAV along the bulkhead next to the ramp as we returned here and found much less SAV than was here in 2008-2010, especially than in 2009 when this whole area had SAV.  This year the SAV was limited here to a few sparse clumps of Ms and Va; this photo of Howard returning to the launch site shows no flat water, while in 2009, most of this area had dense SAV, as was visible in this photo from 2009 of roughly the same area (looking across rather than up that cove).

Mark Lewandowski plan to go soon to survey the other area where wild celery & redhead grass survived and spread after planting, in Longs Cove at Rocky Point Park at the mouth of the Back River. See my report from that creek from 2010.

Tags: SAV Observations · SAV Restoration

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