Last month's Nor'Easter is a striking example of how a series of worse case scenarios add up to create havoc and destruction on a statewide basis. Start with frozen and snow covered grounds that kept any rainwater from being absorbed into the soil. Add to that the previous fall storms and January thaw, which had already raised groundwater to relatively high levels. Then add the seven-plus inches of rain that pelted the landscape in a short period of time. The result was an impressive display of the power of flowing water. In fact, the US Geological Survey reported the highest flows ever recorded for five of the rivers in southern New Hampshire.

The infamous Mother's Day floods of last year, however, actually recorded a higher total rainfall level (in Durham that storm totaled just over 11 inches compared to the 7.5 inches for last month's storm). While that storm resulted in substantial damage in select areas of the state, the ground was snow and ice free, most of the trees had leafed out and spring vegetation was sprouting. The protection that vegetative cover affords against the force of water is substantial. Leaves, branches and stems absorb much of the potential energy of rainfall. Extensive root systems hold the soil in place.

Overland water flow from storm events and thaws is called "runoff." As we clear the land of natural vegetation and our communities spread outward, we increase the occurrences of runoff through the creation of impervious surfaces. Impervious surfaces like roads, roofs, parking lots and compacted areas allow water to collect and flow as opposed to vegetated areas and wetlands that allow water to pond and infiltrate into the ground. The more we can limit and breakup these impervious areas and promote more vegetated areas, the less runoff and erosion will result. This can be done on individual properties as well as through innovative community planning.

To learn more about how landscaping choices can actually improve water quality by treating runoff situations, refer to UNH Cooperative Extension's newest publication: "Landscaping at the Water's Edge: An Ecological Approach to Shoreline Landscaping."