1. Estimate of depth of the littoral zone in a lake.

In 1986, researchers from the University of Alberta gathered data from 12 Alberta lakes on the maximum depth of rooted plant colonization (MDRPC, m) and the Secchi depth (S, m). The maximum depth of rooted plant colonization is the lower boundary of the littoral zone. Secchi depth provides an indication of light attenuation in lake water. These data were combined with existing information on 32 other low-colour lakes and a model was developed to predict the maximum depth of rooted plant colonization:

(MDRPC)0.5= 0.69 log10(S) + 1.76

This model was used to estimate the depth of the littoral zone for many lakes described in the Atlas.

Reference: Chambers, P.A. and E.E. Prepas. 1988. Underwater spectral attenuation and its effect on the maximum depth of angiosperm colonization. Can. J. Fish. Aquat. Sci. 45:1010-1017.

2. Conversion Factors for Gram Weight to Equivalence. (Multiply gram weights by these factors)
Chemical and initial units to Conversion factors
µEQ/L µmol/L
alkalinity mg/L (CaCO3) 19.98 -
total hardness mg/L (CaCO3) 19.98 -
HCO3 mg/L 16.39 16.39
CO3 mg/L 33.32 16.66
Mg mg/L 82.28 41.14
Na mg/L 43.50 43.50
K mg/L 25.58 25.58
Cl mg/L 28.21 28.21
SO 4 mg/L 20.82 10.41
Ca mg/L 49.90 24.95
TP, TDP, SRP µg P/L N/A 0.03228
N µg N/L (for NO3, NO 2 ) 0.0174 0.0174
Kjeldahl N, µg N/L N/A 0.0174
Fe .tg/L (for Ferrous Fe) 0.0358 0.0179
Fe p.g/L (for Ferric Fe) N/A 0.0179
Prepared by: Dr. J. Curtis, Univ. Alta. Dept. Zool.

3. Phosphorus loading coefficients used in the Atlas of Alberta Lakes.

For the 24 lakes described in the Atlas where Alberta Environment calculated phosphorus loading, information was generated from measurements made at the lake wherever possible. However, often there was insufficient infor­ mation on the target lakes, and general coefficients, based on data collected in Alberta, had to be used. Similar general coefficients were used by re­ searchers at the University of Alberta when phosphorus budgets were constructed. The same general coefficients were used by both groups, except for precipitation/dustfall as indicated below.

(1) precipitation/dustfall (where m2 refers to the surface of the lake)

22 mg total phosphorus/m2 per year (Alberta Environment) (Alta. Envir. n.d.)

20 mg total phosphorus/m2 per year (University of Alberta) (Shaw et al. 1989)

(2) watershed (where ha refers to relevant surface area of the drainage basin) (Alta. Envir. n.d.).

: forest/bush - 0.1 kg total phosphorus/ha per year agricultural/cleared

: -0.2 kg total phosphorus/ha per year for light agriculture,

: -0.5 kg total phosphorus/ha per year where intense agricultural practices employed

: residential/cottage - 1 kg total phosphorus/ha per year

: upstream lakes - phosphorus loading to upstream lakes was calculated with loading coefficients applied to the watershed of the upstream lake, and a retention factor for the lake was calculated (Larsen and Mercier 1976). The portion of the phosphorus load not retained by the upstream lake was assumed to enter the lake downstream (for example, Island Lake).

(3) sewage: the amount of sewage actually entering a particular lake was not measured. Instead it was assumed that 4% of the total potential sewage effluent generated by cottages and campgrounds on the lake shore entered the lake. This value was based on an intensive study conducted on Wabamun Lake (Mitchell 1982).


Alberta Environment. n.d. Envir. Assess. Div., Envir. Qlty. Monit. Br. Unpubl. data, Edmonton.

Larsen, D.P. and H.T. Mercier. 1976. Phosphorus retention capacity of lakes. J. Fish. Res. Bd. Can. 33:1742-1750.

Mitchell, P.A. 1982. Evaluation of the "septic snooper" on Wabamun and Pigeon lakes. Alta. Envir., Poll. Contr. Div., Water Qlty. Contr. Br., Edmonton.

Shaw, R.D., A.M. Trimbee, A. Minty, H. Fricker and E.E. Prepas. 1989. Atmospheric deposition of phosphorus and nitrogen in central Alberta with emphasis on Nar­ row Lake. Water, Air, and Soil Poll. 43:119-134.

4. Methods used for analysis of lake water. Same indicates that a similar approach or method was used in both institutions for the parameter indicated.
Parameter Methods
University of Alberta Alberta Environment
temperature 0.5- to 1-m intervals, resistance thermometer Hydrolab meter #4041
dissolved oxygen Winklera within 24 hrs

Hydrolab meter #4041, calibrated to Winkler

pH Metrohm E588 pH meter immediately after collection or Beckman Expandomatic SS-2 meter in the laboratory Hydrolab meter #4041, in situ
total alkalinity potentiometric titrationb, within 24 hours same
specific conductivity YSI model 31 conductivity bridge at 20oC conductivity meter at 25oC
total dissolved solids filter through 0.45-µm membrane filter, evaporate at 103oC calculatedc
total hardness titrate with EDTAb can also be calculated from Ca + Mgd automated calmagite colorimetric methodc
colour Hellige Aqua Tester model 611A within 7 days -
turbidity Hach turbidimeter model 2100A within 7 days same
total particulate carbon thermal combustionb samec
dissolved organic carbon thermal combustionb same
HCO3 , CO3 from alkalinity same
Mg, Na, K, Ca atomic absorption spectrophotometerb Mg, Ca-same. Na, K- automated flame photometryc
SO4 turbidimetric methodd automated methyl- thymol blue colorimetric methodc
Cl automated thiocyanate colorimetric methodb samec
total phosphorus potassium persulfatee in most cases, same
total dissolved phosphorus filtered through 0.45-µm HAWP Millipore membrane filter, then as TP in most cases, same
soluble reactive phosphorus filtered as TDPf


total Kjeldahl nitrogen-N acid indigestiong, followed by NH4-N analysis, modified by Prepas and Trew (1983) semi-automated block digestion, phenate
N02 - N03 -N autoanalyzerh automated cadmium reduction methodc
NH4 - N Solarzano's (1969) phenolhypochlorite method automated phenate colorimetric methodc
total iron phenanthroline methodd atomic absorptionc
chlorophyll a spectrophotometric technique ethanol extractiont (M.L. Ostrofsky described ini) fluorometric procedure acetone extractionk, t

Note: ttwo techniques give comparable results (Prepas and Trew 1983)

Sources: aCarpenter 1965; bEnvir. Can. 1979; cAlta. Envir. Centre 1987; dAPHA 1980: eRiley and Prepas 1984; fMurphy and Riley 1962; gD'Elia et al. 1977: hStainton et al. 1977; iBergmann and Peters; kYentsch and Menzel 1963. More details on the approaches used can be found in Prepas and Trew (1983) and Alta. Envir. Centre (1987).


Alberta Environmental Centre. 1987. Methods manual for chemical analyses of water and wastes, Revised by F.P. Dieken. pubi No. AECV87-M1. Alta. Envir. Centre, Vegreville, Alta.

American Public Health Association. 1980. Standard methods for the examination of water and wastewater. 15th ed. APHA. AWWA, WPCF. Washington, D.C.

Bergmann and R.H. Peters. 1980. A simple reflectance method for the measure­ ment of particulate pigment in lake water and its application to phosphorus-chlorophyll-seston relationships. Can. J. Fish. Aquat. Sci . 37:111-114.

Carpenter, J.H. 1965. The Chesapeake Bay Institute technique for the Winkler dis­ solved oxygen method. Limnol. Oceanogr. 10:141-143,

D'Elia, C.F., P.A. Steudler and N.Corwin. 1977 . Determination of total nitrogen in aqueous samples using persulfate digestion. Limnol. Oceanogr. 22:760-764.

Environment Canada. 1979. Analytical methods manual. Inland Waters Directorate, Water Qlty. Br., Ottawa.

Murphy, J.A. and J.P. Riley. 1962. A modified single solution method for the determi nation of inorganic phosphate in natural waters. Anal. Chim. Acta 27:31-36.

Prepas, E.E. and D.O. Trew. 1983. Evaluation of the phosphorus-chlorophyll relation­ship for lakes off the Precambrian Shield in western Canada. Can. J. Fish. Aquat. Sci. 40:27-35.

Riley, ET. And E.E. Prepas. 1984. Role of internal phosphorus loading in two shallow, productive lakes in Alberta, Canada. Can. J. Fish. Aquat. Sci. 41:845-855.

Solorzano, L. 1969. Determination of ammonia in natural waters by phenolhypochlo­rite method. Limnol. Oceanogr. 14:799-801.

Stainton, M.P., M.J. Capel and F.A. Armstrong. 1977. The chemical analysis of freshwater. 2nd ed. Fish. Envir. Can. Miscellaneous Special Publ. 25 (available from the Freshwater Inst., Winnipeg, Manitoba).

Yentsch, C.S. and D.W. Menzel. 1963. A method for the determination of phytoplankton chlorophyll and phaeophytin by fluorescence. Deep-Sea Res. 10:221-231.