The Impact of Water Clarity on Home prices in Manitowoc County A Report by Dr. David Wolf, Dr. Thomas Kemp and Ms. Megan Roehl

Monetary Valuation is a means of comparing policy options among those without shared values. Hedonic Modeling estimates the value of specific attributes within a larger set of attributes.

Secchi disk readings vary seasonally with changes in photosynthesis and therefore, algal growth. In most lakes, Secchi disk readings begin to decrease in the spring, with warmer temperature and increased growth, and continue decreasing until algal growth peaks in the summer. As cooler weather sets in and growth decreases, Secchi disk readings increase again. (However, cooler weather often means more wind. In a shallow lake, the improved clarity from decreased algal growth may be partly offset by an increase in concentration of sediments mixed into the water column by wind.) In lakes that thermally stratify, Secchi disk readings may decrease again with fall turnover. As the surface water cools, the thermal stratification created in summer weakens and the lake mixes. The nutrients thus released from the bottom layer of water may cause a fall algae bloom and the resultant decrease in Secchi disk reading. Erosion from rainfall, runoff, and high stream velocities may result in higher concentrations of suspended particles in inflowing streams and therefore decreases in Secchi disk readings. On the other hand, temperature and volume of the incoming water may be sufficient to dilute the lake with cooler, clearer water and reduce algal growth rates. Both clearer water and lower growth rates would result in increased Secchi disk readings. In most lakes, the impact of color may be insignificant. But some lakes are highly colored. Lakes strongly influenced by bogs, for example, are often a very dark brown and have low Secchi readings even though they may have few algae.

Satellite inferences of Secchi depth can be obtained through Satellite Radiometry. Euphotic zone depth, an important indicator of ecosystem state, can be predicted from ZSD.

Lake trophic condition Carlson TSI SDT (ft.) Chl-a (µg/L) TP (µg/L) Oligotrophic <38 >15 <2.2 <10 Mesotrophic 38–48 7.5–15 2.2–6 10–20 Eutrophic 49–61 3–7.4 6.1–22 20.1–50 Hypereutrophic >61 <3 >22 >50 TSI, Trophic State Index; SDT, secchi-disk transparency; Chl-a, chlorophyll a; TP, Total Phosphorus; ft, feet; µg/L, micrograms per liter]

Water Clarity by Satellite Imagery 8372* Transactions Home Value; Average = $215,000 1374 homes in Manitowoc County within 250m of a lake Mil Rate = 1.46%

1 Meter Increase in Clarity results in 10.85% Increase in Property Value

A 10.85% decrease in Property Value per average Residence is $23,327. It is $32,051,300 lost Countywide

Value of Lakes: Property Value Swimming Fishing Water Sports Boating Ecological Scenic Intensity of Development

Q1. What do you think is the best feature of living in Manitowoc County? Lake Michigan - 92 responses Small town atmosphere/community - 53 responses Safe - 34 responses Friendly/Good people - 34 responses High quality of life - 18 responses Amenities, parks, zoo, museum, festivals - 14 responses Low Cost of Living - 12 responses Good place to raise family - 11 responses Family & Friends Here - 10 responses Qualified workforce - 8 responses Beauty - 8 responses Location - 7 responses Quality schools/education - 5 responses Clean - 4 responses Access to I-43 - 4 responses Q2. As an employer, what one thing about Manitowoc County would you change? Attract more business/jobs/employers - 55 responses More skilled labor/training - 45 responses More restaurants/amenities - 19 responses Downtown issues - 19 responses Retain youth - 19 responses Nothing - 18 responses Conservative attitude - 16 responses Negative attitudes/Be more positive - 13 responses City Leaders/government issues - 12 responses Better education system - 7 responses Lower taxes - 7 responses Wage level - 7 responses More development/Growth - 6 responses More shopping - 3 responses

What resources are most important to protect and improve in Manitowoc County? What concerns are most important to devote time to?

Impacts on water clarity: Turbidity Algae Chlorophyll Plant growth

Cost : Benefit Minnesota study determined that 30M cost in lake protection would benefit Riparian Land Values 124M

1 lb. of Phosphorous Creates 500 lbs. of Algae

Water and Sediment Control Basins (Wascobs) capture phosphorus and sediment in a settling basin built in swales in agricultural land.  During heavy rains the phosphorus and sediment are carried in water rushing down through annual crop fields.  The Wascob holds the water and releases it slowly, allowing the phosphorus/sediment to settle to the bottom of the basin. 

Eurasian Watermilfoil can reduce property values by as much as 16%

Green Lake Alum Treatment increased water transparency (Secchi depth) from 9 to 19 feet and changed the color from green to blue, and had no effect on the lake pH or dissolved oxygen concentrations.