U.S. flag

美国政府的官方网站

Dot gov

.gov 表示这是官方的。

联邦政府网站域名通常以 .gov 或 .mil 结尾。在分享敏感信息之前,先要确保正在访问联邦政府网 站。

Https

该网站是安全的。

https:// 可确保您正在连到官方网站,而且您提供的任何信息均已加密并能安全传输.

alert - warning

此页面尚未翻译成[简体中文. 前往 简体中文 页面以该语言获取资源。

Roadway Drainage Modifications

ALTON, NH – The floods of 1990, January 1996 and October 1996 have repeatedly eroded the road and ditches in the southern section of the Town of Alton in Belknap County.

The Mitigation Project replaced six undersized culverts and installed riprap along the ditch line. Increased culvert sizes improved the discharge rate, preventing washouts.

The Town of Alton considers this project a success. June 1998 rains flooded and eroded many other roads in Alton. However, the June rains did not impact the project area, minimizing traffic disruption and municipal costs.

At least $15,000 in damages were avoided in June 1998. Some lessons learned include the need to use pre-cast concrete headers instead of masonry headers. Pre-cast concrete better survives the frost heaves. Also, larger rocks and gravel in ditches are better left exposed. The loam sometimes picks up and clogs the drains and culverts.