7. Rock Creek_Attachment II_SantaFeBMPs.pdf

Rock Creek Stewardship IRSC

ATTACHMENT 2

Santa Fe National Forest Best Management Practices for Road Repair

Rock Creek Stewardship IRSC: Items 5 and 6

Key objectives

Best Management Practices are designed to accomplish the following:

A. Produce a safe, cost effective, environmentally friendly, and practical road design that is supported by and meets the needs of the users.

B. Protect water quality and reduce sediment loading into water bodies.

C. Protect sensitive areas and reduce ecosystem impacts.

D. Maintain natural channels, natural stream flow, and maintain passage for aquatic organisms.

E. Minimize ground and drainage channel disturbance.

F. Control surface water on the road and stabilize the roadbed driving surface.

G. Control erosion and protect exposed soil areas.

H. Implement needed slope stabilization measures and reduce mass wasting.

I. Storm-proof and extend the useful life of the road.

J. Minimize the spread of noxious weeds through pressure washing equipment transported onto Forest lands from other areas.

Section 4.1: Key Road Repair Items

A. Grading and shaping the roadway surface to maintain a distinct in-sloped, out-sloped, or crown shape to move water rapidly off the road surface.

B. Compacting the graded roadway surface to keep a hard driving surface and prevent the loss of fines. Replace surfacing material when needed. Keep the road surface moist during grading and compacting.

C. Trimming roadside vegetation (brushing) adequately, but not excessively, for sight distance and traffic safety. See Figure 4.1 below.

Figure 4.1: Vegetation clearing limits.

Section 4.2: Recommended Practices for Road Repair

General Repair and Grading

a) Maintain positive surface drainage with an out-sloped, in-sloped, or crown roadway section using 3 - 5 % cross slopes (up to 5% is best). Provide cross drainage with culvert pipes or rolling dips. In slippery soils, either in-slope the road or add aggregate surfacing to the road. Use a crown road section on a wide road with gentle slopes or flat ground to prevent water from standing on the road surface. See Figure 4.2 below.

Figure 4.2: Road surface drainage design.

b) Roll grades or undulate the road profile frequently to disperse water, particularly into and out of stream crossings.

c) Keep the downhill side of the road free from a berm except where a berm is intentionally constructed to control water or traffic.

d) Apply a surface stabilization material, such as aggregate, cobblestone, or pavement, to the road surface to protect the roadbed from damage and reduce the frequency of Repair needed.

e) Avoid disturbing soil and vegetation if not necessary. Leave as much vegetation (grasses) in ditches, on road shoulder areas, and on cut or fill slopes (especially grasses and low growing brush) as possible. However, ensure sight distance and that the drainage systems still function properly.

f) Remove slide material from the roadway or inside ditches where the material will block normal roadway surface drainage.

g) Avoid widening the road or over-steepening the fill slopes formed by blading surface material off the road.

h) Close the road during very wet conditions or periods of inactivity. If the following guidelines are exceeded, this may be a threshold to either temporarily close the road or schedule heavier Repair to allow use during wet conditions.

1. Unpaved Local Terminal and Service roads: 6 – 8 inch rutting for a maximum of 75 feet not to exceed 10% of total road length. Where surfacing has been placed on the road, see standard for Collector Road.

2. Collector and Arterial Roads: 3 inch rutting for entire length of road if surfaced.

If unsurfaced the guideline will be the same as for Local Service.

3. Drainage: Existing grade dips. If rutted to the point of being non-functional, grade dips will be restored before hauling can continue. Lead-out ditches, roadside ditches and catch basins will be maintained in a functional state.

i) Maintain a 3-5% road cross-slope with in-sloping, out-sloping, or a crown to rapidly move water off the road surface.

j) Grade or maintain the roadway surface before significant potholes, wash boarding, or ruts form.

k) Compact the embankment material, road surface material or aggregate during construction and repair to achieve a dense, smooth road surface and thus reduce the amount of water that can soak into the road.

l) Stabilize the road surface in sensitive areas near streams and at drainage crossings to minimize road surface erosion.

m) Use project construction quality control, through visual observation and materials sampling and testing, to achieve specified densities and quality, well-graded road materials.

Drainage Systems

a) Construct rolling dips rather than culvert cross-drains for typical, low volume, low speed roads with grades less than 12%. Construct rolling dips deep enough to provide adequate drainage, angled 0-25 degrees from perpendicular to the road, with a 3-5% out-slope, and long enough (50 to 200 feet) to pass vehicles and equipment. In soft soils, armor the mound and dip with gravel or rock, as well as the outlet of the dip. See Table 4.1 and Figure 4.3 below.

Table 4.1: Recommended Maximum Distance Between Rolling Dip or Culvert Cross Drains (feet)

Road Grade % Drainage Spacing (ft)

0-3 250 4-6 165 7-9 130

Figure 4.3: Grade Dip Drawings

PRACTICES TO AVOID

a) Long sustained road grades that concentrate flows.

b) Discharging water onto erosive, unprotected soils.

c) “Eyeballing” grades in flat terrain. Use a clinometer, abney level, or survey equipment to ensure that you have proper slopes or grades.

d) Working with equipment in an unprotected natural streambed.

e) Adversely impacting fisheries with a stream crossing structure.

f) Allowing runoff from roadside ditches to flow directly into streams.

g) Crossing wet areas unnecessarily.

h) Concentrating water flow in meadows or changing the natural surface and subsurface flow patterns.

i) Construction operations or heavy traffic during wet or rainy periods on roads with clay rich or fine-grained soil surfaces that form ruts.

j) Allowing ruts and potholes to form over 2 to 4 inch deep in the roadway surface.

k) Road surface stabilization using coarse rock larger than about 3 inches. Coarse rock is difficult to drive upon or keep stabilized on the road surface, and it damages tires.

l) Using surfacing materials that are fine grain soils, soft rock that will degrade to fine sediment, or clean, poorly graded coarse rock that will erode, ravel, or washboard.

m) In-stream channel gravel extraction operations and working with equipment in the stream.

Section 4.3: Recommended Road Closure Practices

Road Closure Best Management Practices

a) Involve the affected population or road users in decisions regarding road closure, typically using an interdisciplinary process.

b) Temporarily close roads using gates, barricades, or large berms.

c) Install water bars on closed roads to divert water off the road surface.

d) Remove berms that may impede surface drainage on closed roads.

e) Obliterate unneeded roads whenever possible and where cost-effective to provide the highest degree of road removal and land reclamation.

f) Close roads by reshaping the roadbed to maintain natural surface drainage patterns and avoid concentration of water. Revegetate exposed soil as needed on closed roads. A common treatment includes scarification, seeding, and a mulch application to promote grass and brush growth. Trees may be planted. On grades, water-bars should be added.

Figure 4.5: Road closure details.