Lake Level Report – Vegetation

VEGETATION

A section from the Lake Level Monitoring report contained in Staff Report from the December 13, 2012 board meeting material.  This section drafted by district staff.

LLRpt Fig 11One aspect of the decision to not impound as much water as had been done in previous years was the potential impact to the shoreline plant community. In fact it was the concern for the viability of the District’s SOS (Save our Shorelines) program that initiated the Erosion Study (Link) that contributed in many ways to the findings for the recent lake level decision. As a healthy shoreline is integral to the health of the lake it is worth nothing that the District continues to sustain its investment in the SOS program with staff, training programs, a native plant nursery, demonstration sites, and a 75% cash match for shoreline property owners. Additionally, the District paid for the development of the Shoreline Planting Guide (Link), and has since then reinvested in multiple printings of this document, sharing it with property owners, landscapers and the like.

Further the District recognizes with the limits of private property owner participation in the SOS program — to date only six have participated and only two property owners have come forward leading to one site evaluation since the June decision — the best opportunity for restoration currently lies on public property. Not only is this on upland publicly owned parcels such as East Devils Lake State Recreation area where the District has its second demonstration site, but more importantly at all areas around the lake up to the 10.4’ meandered legal boundary of the lake. This areas then includes the ring of the lake from Ordinary High Water which is the 10.4’ to some level near 8.3 which may be consider more or less the Ordinary Low Water. This OLW water is ill defined for Devils Lake, but a 2’ fluctuation in lake stage is often seen through the year.

LLRpt Fig 12

A qualitative approach was taken to evaluating the effects on vegetation from the changes in the lake level impoundment regime. Photographs from 2011 were compared to those from 2012. Photographs were taken at similar lake levels for comparison, however the seasonality of the photos were somewhat varied with 2011 being taken early summer, and 2012 taken in late summer where vegetative growth would assumed to have already reached its apex for the year. While much of the shoreline is armored precluding comparisons based on vegetation and other shorelines are manipulated by other means such as lawn maintenance, a number of side by side comparisons can be made. The most dramatic of these is from the D River itself where a very distinct vegetation line can be observed from the  istorically higher impoundment regimes to what was seen in 2012. Areas not inundated in 2012 were quick to recover with vegetation as can be seen by the parallel lines of vegetation.

Other parcels have similar, but less dramatic observable impacts, and still others what can be basically indiscernible. This is not to be unexpected as the overall water changes were modest, basically ½ foot. One comparison of a area where a sheet piling wall was installed which is now being reclaimed by vegetation is shown here; a slideshow of other photos will be presented.

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Filed under DLWID, Lake Level, Native Re-vegetation

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