Elk Lake: Past and Present –What’s Going on Inside Elk

LakeUniversity of Victoria Environmental Law

Centre29 October 2015

Rick Nordin, British Columbia Lake

Stewardship Society

Lake formed after retreat of glaciers about 10,000 years ago European settlement, land clearing, agriculture 1850-1870 Lake impoundment and increased depth and area 1874 Use as drinking water supply for Victoria up to 1914 and to

the Saanich Peninsula until the 1970s 1950 to present – residential development, 1960 – Pat Bay

Hwy Popular recreation destination 1920s to present: present

annual use 1.5 million user days, 14,000 angler days, national, UVic and local rowing facilities

Significant Events in the Timeline of Elk Lake

Forest removal in the 1800s Dam at the outlet raised the lake level 5 m in 1874 Lake volume increased from 7.87 to 18.82 million m3

Lake surface area increased from 141 to 246 ha Beaver “Lake” pre 1874 very small and surrounded by

“swamp” Pat Bay Highway to service Swartz Bay ferry terminal 1960 Species introductions – fish, bullfrogs, plants and ? Climate change

A lake in disequilibrium

Heavy growth of aquatic plants Deteriorating water quality – especially

cyanobacterial blooms Loss of fish habitat and fishery productivity Introduced exotic species

Perceived Problems at Elk Lake

Some studies and reports by government agencies (Ministry of Environment, Fisheries, Saanich, CRD)

First major water quality study by McKean 1992 (MoE) with WQOs and recommendation for aeration. Attainment of WQOs poor.

CRD 1991 recommended a watershed plan UVic theses / dissertations Nowlin, Davies, Groeneveld Stewardship initiative organized by Golden Rods and Reels 2014 Water quality review 2014 and assessment of recent data 2015 by Nordin Lisa Rodgers MSc thesis Restoration options for Elk Lake by Ontario consultant, draft Sept 2015 New Water Quality Objectives Report by MoE in progress

Previous Studies

Very dense aquatic plant growth out to about 5 m depth Recurring algal blooms which are predominantly

cyanobacteria which pose a serious health risk throughout the year

Deep water oxygen depletion for most of the year limits the benthic productivity of the lake (food for fish, habitat for fish)

Recreational fishing success and satisfaction has declined (anecdotal)

Major changes in fish community has altered food chains and likely affected water quality (opinion)

State of Present Water Quality

Very small watershed in comparison to lake itself Consequently very low “flushing rate” (water exchange) Lake thermally stratifies March through November Because of thermal stratification, very low and or zero

dissolved oxygen (DO) in the deeper waters of the lake for 6 months of the year

The stratification and low DO result in return of phosphorus from the rich bottom sediments to the water column

Phosphorus is the key to controlling algal and weed growth Most of the phosphorus supply to the lake (85%) is internal

load

Elk Lake Basics

Initial fish community – 3 species only (Cutthroat Trout, Brown Bullhead and Prickly Sculpin)

Present new fish species: Rainbow Trout, Carp, Sunfish, Perch, LM and SM Bass

Evidence that there has been major change in the zooplankton and benthic community

Aquatic plants have been actively managed for last 50 years – largely by harvesting

Climate change – increased water temp, longer stratification period and faster growth of plants

Lake ecological change

Much better understanding of fisheries populations – quantification of species, habitat requirements

If a whole lake water quality restoration is to be considered (hypolimnetic aeration or phosphorus binding) considerable planning and testing needs to be done

Management of the aquatic plants requires more understanding and quantification and mapping are essential

Ongoing monitoring and reporting (nutrients, toxins, DO, coliforms) and a view to complete ecosystem health assessment

Science Needs

Need for jurisdictional definitions Need for co-operation between government

agencies as well as academia and NGOs Understanding that are two areas of challenge:

management of aquatic plants and water quality rehabilitation (phosphorus management)

Emphasis the absolute importance of Elk Lake – the ecological, economic and aesthetic value of the lake is beyond valuation and deserves active management

Organizational Needs

Thank You!

Mick Collins, Robert McConnell and GRR Michelle Kehler, Deb Epps, (MoE); Scott Silvestri, Neil Goeller

FLNRO GRR and Rowing Club samplers (Dennis Gedney, Pat Psaila, Jim

MacDonald, Clive Lane, Brian Williams, David Topham, John Garrett) CRD: Laura Kline, Glenn Harris, Dale Green Victoria Rowing Society, Rowing Canada, Victoria City Rowing Club,

Brenda Taylor Camosun College – Steve Gormican and students Intergovernmental Committee (Saanich, CRD, MoE) HCTF, FWFSBC, MoE, BCWF, CWF, Victoria F&G Protective Assn,

Peninsula Streams, Colquitz Coalition ELC especially Calvin Sandborn