Demonstration Design, Treatments and Evaluation

Mark Clark

Wetlands and Water Quality Extension SpecialistPartnership for Water, Agricultural and Community Sustainability at

HastingsSoil and Water Science Department, Gainesville

Overview

• Nutrient loading from the landscape is the source of the algae problem.

• Goal of alternative stormwater pond management is to maintain regulatory function while maintaining aesthetics and use.

• Copper sulfate is very effective at algal control due to its toxicity, but there is concern over cumulative heavy metal additions to water body and its possible negative effect on contaminant removal function of basin.

Goal of Alternative Management Demonstration

• Evaluate several alternative management practices to address algal development in basins and determine costs, acceptability and treatment efficacy.

Demonstration Study Design

• Apply four different treatments to stormwater basins within the Grand Haven community.

– Aeration

– Littoral Shelf Planting

– Submerged Aquatic Vegetation (reduce or eliminate grass carp)

– Copper Sulfate

– No treatmentX

Treatments(Aeration)

• Aeration– Air compressor with micro-

bubble diffusers.– Location within pond and

number of aerators per pond is critical and dependant on pond bathymetry and depth

– Could change selected ponds to minimize cost and take advantage of existing infrastructure if cost are beyond budget estimates.

Treatments(Littoral Shelf Planting)

• Littoral shelves will be planted to a maximum depth of 4 feet with at least four different vegetative species

• Species selection can be modified by CDD if desired.

• Proposed species– Duck Potato– Pickerelweed– Spike Rush– White Water-Lily

• Need to assess carp population in lakes selected for this treatment

Spike Rush (Eleocharis interstincta)Duck Potato, (Sagittaria lancifolia)

Pickerelweed (Pontederia cordata)White Water-Lily (Nymphaea odorata)

Proposed Species

Treatment(Submerged Aquatic Vegetation)• Presence of SAV competes with algae

for nutrients, reduces light, provides aquatic habitat.

• Selected ponds for this treatment will be evaluated for the extent of carp present and may need to be modified if Carp grazing can not be reduced to allow of increased SAV.

Existing Treatment(Copper Sulfate)

• Copper Sulfate will be applied on an “as needed basis” consistent with existing protocols.

• Treatments will be documented and amount of Copper Sulfate applied will be recorded.

Treatment Management

• Need to discuss treatments with Aquatic Management Company

• Need to make all parties in management chain aware of demonstration study objectives.

• Need to make community and especially members living around treatment lakes aware of study goals and objectives.

What will be Evaluated

– Cost• Initial• operational/maintenance

– Algal cover (biweekly)• Aesthetic acceptance (homeowners)• Quantitative measure (photo documentation)

– Water quality (biweekly)• TSS, TN, TP• Water column sample just beyond littoral shelf

– Ecological condition (monthly)• Aquatic fauna – visual inspection• Dip net – visual inspection

Treatment Selection Protocol

• Many criteria evaluated

• “Symptom” criteria selected– Lakes were ranked based on number of

Copper Sulfate treatments in 2006-2008– Treatments were randomly assigned to

top 12 lakes

Lake Ranking Based on Number of Treatments in 2006-2008

0

10

20

30

40

50

6019

618 11

4 2 5 9 8 1 716

310 24 17 25 23 29 13 20 22 14 26 15 28 30 21 31 12 27

Pond Number

Number of Copper SulfateTreatments

Lake Treatment Assignments

• Aeration– 2, 4,11

• Littoral Planting– 7, 9, 16

• Carp control / SAV– 1, 8, 19

• Copper Treatment– 5, 6,18

Map of Treatment Assignments

Aeration

Littoral Shelf Planting

Carp Control / SAV

Copper Sulfate

Expected Issues

• Alternative treatments will not be immediate

• Alternative treatments will not eliminate filamentous algae

• Homeowner education will be critical

Next Steps

• Work with vendors to determine cost – Equipment– Wiring– Plant material

• Coordinate with Lake Management Co.• Educate homeowners on treatment lakes

and “aesthetic” acceptance evaluation• Set planting dates and organize volunteers• Initiate water quality monitoring, algal photo

stations and ecological function monitoring.

1818

1818

1919

16161717