EFFECT OF STORMWATER RUNOFF ON JOE’S CREEK WATERSHED
Preface
On October 10, 2015 Joe’s Creek watershed experienced the first major (1.0 inch) precipitation
event of the wet season (October-March). Prior to this event the sole source of water in Joe’s
Creek, Lake Lorene and Lake Jeane was groundwater discharge (base flow) from the A-3
aquifer. This paper describes the water quality condition of Joe’s Creek, Lake Lorene and Lake
Jeane prior to the October 10, 2015 precipitation event and one day (October 11, 2015) after this
event occurred and provides an interpretation of the data and photos displayed below.
Joe’s Creek’s water quality pre and post precipitation event
On 10/3/15 Joe’s Creek’s (just above Lake Lorene) soluble phosphorus concentration was 0.078
mg/L; nitrate-nitrogen was 1.0 mg/L; alkalinity was 122 mg/L (CaCO3); conductivity was 309
uS. On 10/11/15 soluble phosphorus concentration was 0.033 mg/L; nitrate-nitrogen was 0.5
mg/L; alkalinity was 61 mg/L (CaCO3); conductivity was 18l uS.
Lake Lorene’s water quality pre and post precipitation event
On 10/3/15 Lake Lorene’s (at the outlet) soluble phosphorus concentration was 0.020 mg/L;
nitrate-nitrogen was 0.2 mg/L; alkalinity was 111 mg/L (CaCO3); conductivity was 272 uS. On
10/11/15 soluble phosphorus concentration was 0.042 mg/L; nitrate-nitrogen was less than 0.2
mg/L; alkalinity was 97 mg/L (CaCO3); conductivity was 243 uS. There was no evidence of a
cyanobacteria bloom as noted in the below post event photograph.
Lake Jeane’s water quality pre and post precipitation event
On 10/3/15 Lake Jeane’s (near its overflow outlet) soluble phosphorus concentration was 0.033
mg/L; alkalinity was 115 mg/l (CaCO3); conductivity was 267 uS. A toxic cyanobacteria bloom
was evident. Lake level was approximately 2 feet below the outlet structure lip (left margin).
On 10/11/15 soluble phosphorus concentration was 0.033 mg/L; alkalinity was 110 mg/L
(CaCO3); conductivity was 255 uS. Cyanobacteria scum/fir needles leaving Lake Jeane.
Golf course pond at # 3 hole pre and post precipitation event
On 10/3/15 there was no surface water flow from Lake Jeane to the pond, only subsurface flow
via the golf course irrigation system plumbing. Water had fairly good clarity.
On 10/10/15 surface water from Lake Jeane containing cyanobacteria scum and fir needles was
flowing via a culvert leading to an open channel thence into the pond. Water is turbid.
Joe’s Creek water below the golf course # 3 hole pond post precipitation event
Water from the Twin Lakes Golf & Country Club # 3 pond is discharged into Joe’s Creek below
S 320th. Below is a post precipitation event photograph of the debris covered outlet that
discharges overflow water from the #3 pond via a culvert into Joe’s Creek below S 320th.
Interpretation of the data
Joe’s Creek data
It is obvious from the above data that stormwater runoff into the upper reach of Joe’s Creek has a
dramatic effect (dilution) on the nutrient concentration, alkalinity and conductivity of Joe’s
Creek’s dry season A-3 aquifer discharge base flow chemistry.
Such a result is contrary to the widely held belief that it is stormwater runoff that conveys high
nutrient concentration water into groundwater fed streams and lakes. It is generally not
stormwater runoff flowing into a surface water body, particularly in an urban setting, that
provides the bulk of nutrients that fuel filamentous green algae and cyanobacteria blooms, or in
their absence, excessive native and noxious aquatic plant growth. Rather it is the nutrients
contained in the groundwater that discharges into these water bodies. Eventually, as a result of
continuous external groundwater nutrient loading, the accumulated nutrients in bottom sediments
begin to release nutrients that have built up over the years of nutrient loading by discharging
groundwater. Nutrient release from sediments is referred to as internal nutrient loading and
generally occurs in the latter stage of a lake’s nutrient pollution degradation.
It is also obvious that stormwater runoff significantly increases the volume of water in the upper
reach of Joe’s Creek and that which passes through Lake Lorene, Lake Jeane, # 3 golf course
pond and into lower Joe’s Creek.
Lake Lorene’s data and photo
Whereas Joe’s Creek was discharging high soluble phosphorus (0.078 mg/L) and nitrate-nitrogen
(1.0 mg/L) concentration water into Lake Lorene during the dry season (pre precipitation event)
the soluble phosphorus (0.020 mg/L) and nitrate-nitrogen (0.5 mg/L) concentration in the water
leaving Lake Lorene was much lower. The explanation for this phenomenon is that Lake Lorene
was treated with zero valent iron to inactivate soluble phosphorus in the lake and that
filamentous green algae growing in Lake Jeane assimilated (thus removing) a portion of the
nitrate-nitrogen from Joe’s Creek inflowing water.
The high soluble phosphorus concentration (0.042 mg/L) condition that Lake Lorene
experienced after the precipitation event was likely due to phosphorus laden surface water runoff
from Treasure Island’s goose feces loaded lawn and walkway areas.
Lake Jeane’s data and photos
During the dry season Lake Jeane receives water from two sources. One source is the pass
through of Joe’s Creek water after its conditioning in Lake Lorene. The other source is irrigation
well water pumped into Lake Jeane to make up for the quantity of water withdrawn from Lake
Jeane by the golf course’s irrigation system. The Twin Lake Golf & Country Club’s irrigation
well withdraws groundwater from the A-3 aquifer. A-3 aquifer groundwater in Joe’s Creek
watershed (which also discharges into the upper reach of Joe’s Creek) has soluble phosphorus (~
0.080 mg/L) and nitrate-nitrogen (~2.0 mg/L) concentrations that are considerably higher than
A-3 aquifer groundwater underlying undeveloped areas in the Puget Sound Basin. This
condition is likely due to human activity (septic system effluent, surface water management
practices) taking place above the A-3 aquifer.
For some unannounced reason the TLG&CC elected to discontinue the practice of pumping
irrigation well make up water into Lake Jeane while still withdrawing irrigation water from Lake
Jeane to irrigate the golf course for several weeks prior to the time the above photograph of the
low Lake Jeane water level was taken.
The likely explanation for why the soluble phosphorus concentration pre (0.033 mg/L) and post
(0.033 mg/L) precipitation event remained unchanged in Lake Jeane in spite of the large volume
of water from Joe’s Creek that completely filled to overflowing Lake Jeane is that the soluble
phosphorus concentration of Joe’s Creek’s pass through water was also 0.033 mg/L.
Golf course # 3 pond photos
It is obvious from the two photos that the golf course # 3 pond that when the pond was receiving
water withdrawn from below the surface of Lake Jeane (pre precipitation event) the pond’s water
was relatively clear and devoid of cyanobacteria scum material whereas when Lake Jeane filled
and the cyanobacteria scum was flowing via the lake’s overflow structure, culvert and open
channel into golf course # 3 pond that its water became turbid and loaded with cyanobacteria and
their released toxins.
The post precipitation cyanotoxin laden discharge from the golf course # 3 pond likely loaded
Joe’s Creek below E 320th St with potentially hazardous to salmon and wildlife cyanotoxins.
Conclusion
It is the nutrients (phosphorus and nitrate-nitrogen) contained in A-3 aquifer groundwater that is
discharging 24/7/365 into the upper reach of Joe’s Creek that is fueling filamentous green algae
and pre management cyanobacteria population explosions (blooms) in Lake Lorene. It is the
pass through of nutrient conditioned water from Lake Lorene into Lake Jeane and the A-3
aquifer groundwater being pumped from TLG&CC’s irrigation well water into Lake Jeane that is
fueling its dry season hazardous cyanobacteria blooms.
To be determined is whether the high nutrient concentrations in A-3 aquifer groundwater is a
natural condition (which I doubt) or a human activity induced condition (which is likely) and
should be the focus of the City of Federal Way’s Aquatic Algae Control Program grant funded
project.
Whether it is determined that the high nutrient condition in Joe’s Creek watershed is a natural
condition or due to human activity induced nutrient pollution of A-3 aquifer groundwater (that is
amenable to mitigation) the fact remains that for the foreseeable future both Lake Lorene and
Lake Jeane are going to have to be proactively managed to inactivate the phosphorus that fuels
cyanobacteria population explosions (blooms), suppress filamentous green algae growth and, as
the water in these two managed lakes becomes less turbid, to prevent excessive aquatic plant
growth.
In exchange for it use of Joe’s Creek’s water for irrigating its golf course the Twin Lakes Golf &
Country Club has an obligation to mitigate the adverse impact that cyanobacteria blooms and
their released toxins in Lake Jeane is having on Lake Jeane shoreline property owners, golfers
and the lower reach of Joe’s Creek’s salmon and Dumas Bay’s shellfish.
There currently exists cost effective technology for inactivating phosphorus and negating the
effects (filamentous green algae blooms) of nitrate-nitrogen pollution. The TLG&CC
management should begin to focus their attention on examining these options and select and
implement those that will assure the health of Lake Jeane shoreline residents, its golfing
members and the passage of cyanotoxin free water into the lower reach of Joe’s Creek and
Dumas Bay.
Don Russell
10/13/15