The results indicate that the asperity height and the maximum mean depth were significantly reduced after the friction tests.
From the profile ordinate data read at 1 μm intervals, a number of surface roughness parameters – centre line average, root-mean-square roughness, maximum height, maximum mean peak height, maximum mean depth, and absolute average asperity slope were calculated using a computer program.
A number of surface roughness parameters, viz., the center line average (CLA, Ra) and root mean square (RMS, Rq) roughness, maximum mean peak-to-valley height (Rtm), maximum mean peak height (Rpm), maximum mean depth (Rvm), and average asperity slope (Δa) were calculated.
Univariate regression analyses demonstrated that these macrophyte cover metrics are predicted by a wide range of predictor variables, most commonly by: Secchi disk depth, maximum or mean depth, catchment morphometry, road density and the proportion of urban or agricultural land use/cover in the riparian zone or catchment (r2 = 0.06 0.46).
Based on the available data, we found no significant difference in maximum or mean depth between European and North American lakes (Figure 3), nor between the North American lakes that exhibited increased or decreased DI-TP post-1945 (data not shown).
Rather, we flagged errors and egregious values that 1) do not make ecological sense, 2) are well beyond what has been detected in previous studies, 3) are not technically feasible (e.g., lake mean depth > maximum depth), or 4) are indicated as 'not available' when data exist.
The Baltic Sea is very shallow, with the maximum depth of 460 m and mean depth of 60 m.
The study was conducted in Lake Krankesjön, a 3.4 km2 shallow (mean depth 1.5 m, maximum depth 3.0 m), eutrophic lake in southern Sweden.
Lake Ledoux is a typical small oligotrophic temperate zone lake with respect to surface area (11.9 ha), mean depth (5.5 m), maximum depth (17.0 m), and general physicochemical characteristics [25].
Lake Zürich in Switzerland (47°15'N, 8°38'E, 406 m above sea level) is a deep (mean depth 51 m, maximum depth 136 m), monomictic lake with a surface area of 68 km.
On the other hand, Bolsena is a freshwater (salinity of 0 ‰) mid-sized lake of volcanic origin, with a 113.6 km surface, a maximum length of 13.5 km and a mean depth of 81 m.
