City motor grader leveling dirt street.

Dirt Street Maintenance

Dirt street grading is to provide a smooth driving surface that is shaped to accommodate traffic, run-off, and slope limitations within City of Helena right-of-way.

There are several factors, which determine methods of maintaining City dirt streets.  They are: slope, traffic, and historical placement within City right-of-way. Dirt streets are generally bladed twice a year, in May/June and October/November.  The Street Division's objective is to maximize the useful life of the roadway and provide the best driving surface for the longest duration under all conditions. To accomplish this, several general principles have been adopted: the steeper the slope the heavier the material used (pit run versus ¾ road mix); the heavier the load the heavier the material (pit run with large rock for heavy truck traffic); the more traffic volume the heavier the material (more traffic volume requires a pit run base); a crown or cross slope of at least 4% shall be placed on the surface to keep water from the driving surface and into ditches or gutters; culverts are encouraged for access approaches where necessary .

Alley Grading

Alley grading is done to shape the surface within the city right of way to desired specifications.  Alleys are maintained to accommodate access to properties, garbage pick-up, and runoff.  Several factors influence grading and maintaining alleys including access from streets, right of way width and location, adjoining properties and their structures, slope(s), utilities, and parent material.

The Street Division has embarked upon a program of concentrated grading within neighborhoods that address recurring problems in alleys.  Our objective is fourfold;  1) provide a cross-slope that channels runoff onto one side of the alley that minimizes flooding onto lower elevation properties; 2) provide a uniform slope(s) to adjacent streets wherever possible; 3) provide adequate access to adjacent properties where possible; 4) provide a smooth durable surface within physical limitations.

Property owners are responsible for keeping alleyways clear of debris and overgrowth of trees and shrubs to allow for garbage pick-up and alley maintenance.