Infestation: Since Mount Holyoke acquired Upper Lake and Lower Lake they have become spots of recreation and relaxation. From swimming and wading to boating or just enjoying the outdoors the lakes have become a cherished place to Mount Holyoke College as well as to the surrounding community. But all this changed when the Water Chestnuts came with their plans of taking over. Water Chestnuts make any activity in or around the lakes dangerous due to the sharp spikes that the chestnuts have. They can be harvested and sold for profit but if left to their own devices they would end up out-competing everything else that lived in the lakes as well as making the lakes unusable for recreation and enjoyment. There food value is far outweighed by the negative effects the Water Chestnuts have on recreation and ecology. (21)

To see more pictures of Water Chestnuts and for a more indepth facts on the Water Chestnut click here.

Action: Because of this the college called in the experts to try and eradicate the Water Chestnuts from the lakes. In 1948 Massachusetts issued the Water Chestnut Control Program due to the fact that these pests were becoming a major problem in and around Massachusetts (21). Water Chestnuts had been such a hard species to control that signs and fliers were issued around Massachusetts asking people if they saw any water chestnuts to report the sighting to the Phillips Wildlife Lab in Upton Massachusetts immediatly so action could be taken(22). The huge worry was that the Water Chestnuts would end up taking over many of the lakes around Massachusetts and surrounding areas which would limit boating, hunting, picnicking and many other outdoor activities.

Eradication: The Water Chestnut Control Program had quite a few ways of dealing with the problem although some of the methods proved more effective in the long run than others. Spraying in conjunction with mowing (harvesting) was the first method that was usually tried due to the fact that it proved to require the least amount of time and effort to carry out. Ecologically though it was a nightmare. Basically they were spraying pesticides (#2 Fuel oil was used at the time) on the Water Chestnuts that caused them to die but this lead to pesticides in the water and the surrounding environments as well as causing a major build up of detritus on the lake bottom. Also the spray was brought out to the lake using a truck at a time when there were no roads around Upper Lake so the truck sank in the soft fields many times further degrading the environment. Hand pulling was also tried in some cases but was found to be far to labor intensive to be effective. (21) When none of the above methods proved effective in terms of eradicating the Water Chestnuts drastic methods were undertaken including draining the lake which was the case for Upper Lake.

Click here for the Water Chestnut distribution in Upper Lake in 1948.

In 1949 action was taken to end the Water Chestnut infestation of Upper Lake. Upper Lake was completely drained in an attempt to kill the invasive species in the hopes that exposing the roots of the plants to direct sunlight would kill them. This method was utilized due to the fact that spraying didn’t work as well as planned. One of the main reasons aside from the impediment of recreation was that the state wanted to make sure that the Water Chestnuts did not get into the Connecticut River. After the lake was drained and the plants died they were removed by hand to prevent them from reseeding. The whole process took about a month. (23) To read more about draining and dredging the lakes click here. In 1985 the Water Chestnuts were back in full force so the college harvested them from Lower Lake to prevent them from outcompeting all of the other life in and around the lake.

Ecological Implications: Ecologically Water Chestnuts are an invasive species that takes over and out-competes most of the native vegetation. They “clog water ways, crowd out vegetable food for wildlife and encourage mosquitoes to breed." This causes problems not only for the native vegetation but also for the wildlife that lives in and around the lake who have to adapt to this new species that completely takes over. Although the removing of the Water Chestnuts disturbs the surrounding environment to the extent of possibly harming it, it is better that letting the exotic Water Chestnuts take over because in the long run the chestnuts will do more damage to the environment by decreasing the overall diversity. A decrease to overall diversity decreases the environments ability to react and adapt to perturbations making it less stable and resilient.

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1. The Creation of the Mount Holyoke College Landscape

3. Disasters and Other Odd Occurances and Changes