Beach Water Quality Study 2003:
Some Answers, More Questions
By Jack Ellis
Background. Over the past few years, concern over water quality at Tiny beaches has grown. More frequent postings of once crystal clear beaches are signs of real problems. In 2001, the Federation organized a huge program of water quality sampling along the 72 kilometres of Tiny’s shore (including Farlain Lake) to augment the weekly samples taken by the Health Unit at a few locations. The Federation raised $7,000 to finance the tests on samples collected by volunteers. This effort was continued in 2002 and 2003 by various beach associations interested in tracking the water quality in their local areas. The results of these volunteer studies are posted on http://www.tinycottager.org.
These years of intensive sampling showed there were indeed some serious problems. What was needed next was further study to determine what factors cause the pollution, where is it coming from, and what should be done about it.
In 2003, the Township of Tiny commissioned a $40,000 study directed by Keith Sherman, Coordinator of the Severn Sound Environmental Association (SSEA), in partnership with the Simcoe County District Health Unit (SCDHU) to investigate the factors affecting beach quality. Three beaches, including the immediate watersheds draining to each beach area, were chosen for investigation: Balm Beach, Jackson Park Beach and Woodland Beach.
The complete report “An Investigation of Water Quality on the Coast of the Township of Tiny” including all figures and tables is available in PDF format on the Tiny Cottager and the Township websites. What follows conveys key points in the report, sometimes using the exact words, sometimes concentrating them, sometimes in summary.
Pollutants and sources. E. coli bacteria are the main indicator of health risks (although many other parameters were also measured). The Health Unit has the obligation to recommend posting of a beach as unsuitable for swimming when their E. coli sample measurement exceeds 100 orgs/100 ml of water.
Potential sources of bacteria include: discharge from faulty or substandard private sewage systems, runoff from built up areas adjacent to beaches, the impingement of streams and ditches discharging at or near the beaches, the bathers themselves (in case of high densities of bathers), animals and birds which defecate on the beach or in the water.
Other factors include: the degree of sheltering of the beach from wind and wave action and lake currents, water temperature, the lake bed conditions, and water column turbidity.
The 2003 beach studies tried to discover:
• what are the sources of bacterial contamination that influence these beaches?
• how do the densities of E. coli vary at or between beaches and with time in relation to potential sources and other factors? Specifically:
• are there changes in bacterial counts seasonally from July to September?
During dry weather (no rain in previous 48 hrs) SSEA collected samples at selected sites within the immediate watershed of each beach to characterize sources of bacteria that could impinge on the beach.
Study Approach
• SCHDU staff sampled the beach quality and shared past and current information with the SSEA.
• SSEA monitored the beach locations during
several rain events, sampling for E. coli and additional parameters.
• The beach use on weekends was documented by Township staff through surveys and photographs.
Five sampling locations were routinely measured at Balm and Woodland Beaches and six at Jackson Park Beach because of the length of beach.
Study areas and findings. Surveys showed that the beaches received little concentrated use during 2003. Balm Beach was the most heavily used with up to 100 bathers at one time while Woodland Beach was the lowest at 10 bathers. SCDHU periodically recommended posting of all three beaches, with Balm exceeding the allowable standard 5 times, Jackson
4 and Woodland 10 times.
The following factors were found to have only a minor effect on beach pollution:
• bather density and volume
• birds and animals
• water temperature
• beach grooming
Some factors have a potentially moderate effect:
• lake bed conditions
• winds
• sheltering of the beach
Streams and outfalls are the major sources of bacteria, often having E. coli densities above 100 orgs/100 ml during dry weather and much higher during wet weather. The E. coli densities were found to increase from upstream locations to downstream locations, likely from sources originating in the built-up zone. Also, E. coli densities in the streams increased from spring to early summer, suggesting that the active occupation of dwellings at the start of the recreation season affects the quality of the streams.
The rain events studied were relatively small and commonly occurring. In the case of Balm Beach, water quality deteriorated within one hour of the onset of the storm event. The other beaches sampled showed more variable responses but with longer response times, in excess of five hours. Beach quality returned to levels consistent with dry weather within 24 to 48 hours.
Balm Beach. The area draining to Balm Beach is approximately 260 ha. Approximately one-third of the upper watershed is intensive cropland (soy beans and grains) with one-third being idle farmland and one-third forest covered. The Balm Beach wetland is a provincially significant wetland located between the bluffs and the urbanized shore areas from Balm Beach to Jackson Park.
Within 1 hour of the July 15th rain event (20 mm) the Balm Beach streams E. coli densities jumped to over 6,000 orgs/100 ml. The area of Balm Beach closest to the main stream discharge responded shortly after with E.coli densities of more than 1,000 orgs/100ml.
Jackson Park. The area draining to Jackson Park Beach includes a relatively large stream that discharges directly onto the beach (draining 300 ha). A smaller intermittent stream discharges to an area north of the Beach (draining approximately 40 ha). The Jackson Park Beach streams measured the highest base flows. There are also some municipal drains located within the areas draining to Jackson Park Beach. The majority of the Jackson Park Beach sub-watershed consists of swamp land with about 20 % farmland.
The increase in E. coli at Jackson Park Beach after the July 15th rain event was relatively small at the beginning of the storm and peaked more than 20 hours after the onset. The September 22nd storm showed a similar pattern, peaking 10 hours after the event started, returning to normal levels within 24 hours.
Woodland Beach. Two streams discharge to Woodland Beach, the northern stream draining an area of 300 ha and the southern 490 ha. The Woodland Beach sub-watershed is predominantly farmland (approximately 70%). The Woodland Beach stream inflows were very low.
Pollution levels at Woodland Beach did not immediately increase with the rain events, with E. coli in the streams peaking at over 1,000 orgs/100 ml. However, the beach values exceeded 3,000 to 6,000 orgs/100 ml. This strongly suggests that the local streams were not the main source of contamination influencing Woodland Beach during rain events.
Recommendations. To improve the water quality:
• continue to inspect and abate faulty or
substandard private sewage systems.
• consider treating stormwater runoff to provide
retention and reduction of solids and bacteria prior
to discharge near beaches.
• consider moving the stream outlets discharging
directly into the Balm and Jackson Beach coves to
locations off the points for better dispersion and
mixing of their discharge.
Follow up surveys should:
• use PCR/DNA fingerprinting of E. coli strains to
detect their source (animal vs. human).
• install rain gauges along the shore.
• use more continuous methods of tracking the
impact of discharges onto the beach areas.
• survey the lake bed and the temperature regime in
the vicinity of the beaches.
• expand the Woodland Beach study area.
• do detailed follow up surveys of the streams.