BMP Installation Guide — Erosion and Sediment Control for NM Construction
Best Management Practice (BMP) installation in New Mexico requires adapting standard specifications to desert conditions: caliche hardpan, arroyo hydrology, monsoon-intensity storm events, and high-UV high-desert soils. This guide covers the five most commonly installed BMPs on NM construction sites, with NM-specific installation notes throughout.
Silt Fence InstallationFiber Wattle / Straw Wattle StakingRock Check Dam (Arroyo Considerations)Inlet ProtectionTrackout Control Mats
Silt Fence Installation
NMR100000 Section 2.1 / CGP 2022 Appendix B
Silt fence is a temporary sediment barrier consisting of filter fabric supported by wooden or metal posts. In New Mexico, silt fence is a standard perimeter control — but installation failures are the most common CGP deficiency found during NMED and EPA inspections.
NM-Specific Requirements
·Caliche hardpan prevents standard post driving to the required depth (12-18 inches minimum). Use pneumatic or hydraulic post drivers — hand driving is not adequate in most NM soils.
·J-hook bottom embedment: trench the fabric at least 8 inches into the soil and compact backfill. In sandy desert soils, backfill with local aggregate, not loose sand.
·Post spacing: 6-8 feet for standard fabric; 4 feet in high-flow areas or arroyo-adjacent zones.
·Fabric selection: Use 3–5 oz/sq yd woven geotextile fabric rated for 0.1–0.5 gpm/sf flow rate. Standard big-box polypropylene is not appropriate for NM monsoon flow velocities.
·Monitor for UV degradation after 6 months. High desert UV at elevation causes fabric breakdown — inspect fabric integrity, not just attachment.
Installation Steps
1Locate fence on the contour — never across drainage swales or perpendicular to flow
2Drive posts to minimum 12-inch depth; 18 inches in caliche zones
3Attach fabric with staples or wire ties — minimum 6-inch overlap at joints
4Trench fabric bottom 8 inches; backfill and compact
5Install at least 3 feet from the toe of the disturbed area where possible
6Document installation with GPS-tagged photos before any rain event
Inspection & Maintenance
Inspect after every storm event ≥ 0.25 inches
Remove sediment accumulation when it reaches 1/3 to 1/2 of fence height
Repair or replace torn, bent, or undermined sections within 24 hours of discovery
Check post stability — monsoon saturation softens soil and can lean posts
Fiber Wattle / Straw Wattle Staking
NMR100000 / CGP 2022 Appendix B
Fiber rolls (also called straw wattles or fiber logs) are cylindrical straw or wood fiber rolls staked to the slope to intercept runoff and reduce erosion velocity. In New Mexico, they are widely used on disturbed slopes, around drainage structures, and as check dams in low-velocity channels.
NM-Specific Requirements
·Caliche penetration is the primary installation challenge. Standard wooden stakes (18" typical) often cannot penetrate caliche hardpan. Use rebar stakes, T-posts driven with a driver, or pre-drilled pilot holes.
·For monsoon-season installation, stake at 2-foot intervals (not 4-foot) in high-flow zones. Flow velocities during NM convective storms exceed design assumptions for standard wattle staking specs.
·Desert soils compact against the wattle over time. Re-check that wattles are seated firmly against the slope — a 1-inch gap under a wattle allows flow to bypass the BMP entirely.
·At elevation above 6,000 ft, use straw-free excelsior or wood fiber rolls — straw wattles can become weed vectors for invasive species in sensitive high desert ecosystems.
Installation Steps
1Install on the contour — follow the slope's topographic contour, not a straight line
2Trench a shallow channel (2-3 inches) on the upslope side to seat the wattle
3Drive stakes through the wattle center at 4-foot intervals (2-foot in high-flow)
4Stake angle: perpendicular to the slope surface, not vertical
5Butt ends of adjacent wattles together — no gaps
6Stake ends down with a T-post or rebar pin to prevent displacement
Inspection & Maintenance
Inspect after every storm event ≥ 0.25 inches
Replace flattened or displaced wattles before the next storm event
Check that stakes are still perpendicular and fully seated — frost heave at elevation can displace stakes
At project end, remove wattle material — do not leave in place for permanent stabilization without seeding
Rock Check Dam (Arroyo Considerations)
NMR100000 / CGP 2022 / NMAC 20.6.5 (draft)
Rock check dams are structures placed across drainage channels to reduce flow velocity, trap sediment, and provide temporary grade stabilization. In New Mexico, they are commonly deployed in arroyos and ephemeral channels — but arroyo hydrology creates design challenges not encountered in perennial stream environments.
NM-Specific Requirements
·Arroyo flow velocities during monsoon events can exceed 10 ft/sec. Standard rock check dam specifications assuming 3-5 ft/sec are not adequate. Size rock to D50 appropriate for expected flow — minimum 8-12 inch rock in arroyo channels.
·Arroyos cut through caliche hardpan and alluvial deposits with variable bearing capacity. Verify channel bed conditions before specifying footing depth.
·Many NM arroyos are not jurisdictional Waters of the US under current federal interpretation — but NMPDES may establish state-level buffer requirements. Inspections Plus evaluates jurisdictional status as part of site assessment.
·Wing walls on check dams must key into the arroyo bank at least 2 feet laterally and 6 inches deep. Bank erosion during monsoon events can remove improperly keyed structures in a single storm.
·Overflow notch: design a center notch 2-3 inches below the structure crest to control overflow location and prevent flanking.
Installation Steps
1Survey channel cross-section and estimate peak flow (Q) for a 2-year, 24-hour storm
2Select rock size based on Shields criterion for expected flow velocity
3Excavate key-in trench for wing walls: minimum 2 ft lateral, 6 inches depth
4Place filter fabric against soil contact (optional in high-velocity channels — fabric can be blown out)
5Set rock by hand or equipment — no rubber-tire vehicles on filter fabric
6Install overflow notch at structure centerline, 2-3 inches below crest
7Document GPS location and pre-construction photo
Inspection & Maintenance
Inspect after every storm event ≥ 0.25 inches
Check for scour at the downstream toe — significant scour indicates undersized rock
Remove accumulated sediment when pool behind dam reaches 50% of design storage
Check wing wall keys — any displacement requires immediate repair before next storm event
Inlet Protection
NMR100000 / CGP 2022 Part II.B.3
Inlet protection prevents sediment-laden runoff from entering storm sewer systems, curb inlets, and drainage structures during construction. Multiple product types are available — the appropriate selection depends on inlet type, drainage area, and flow rate.
NM-Specific Requirements
·Albuquerque area inlets: AMAFCA and Bernalillo County have approved inlet protection product lists. Verify product compliance before installation — non-approved products may not satisfy CABQ inspection requirements.
·Curb box inlet protection is standard for curb-line inlets. Filter bag or geotextile wattle systems are appropriate for flat grate inlets.
·High-volume monsoon events can overwhelm undersized inlet protection. Inspect and clear accumulated sediment before each forecast storm during July–September.
·Sand and caliche fines are very fine-grained — standard inlet filter fabrics must have permeability appropriate for the D50 particle size of your site soils.
Installation Steps
1Select product type based on inlet geometry and drainage area
2Install per manufacturer specifications — ensure secure attachment to prevent displacement
3For curb inlets: block the full curb opening; no gaps at corners
4Mark inlet with contractor ID for inspection record
5Document with GPS-tagged installation photo
Inspection & Maintenance
Inspect after every storm event
Remove accumulated sediment before reaching 50% of ponding capacity
Replace torn or compromised filter media immediately
Remove and dispose of all inlet protection at project completion — do not leave in public right-of-way
Trackout Control Mats
NMR100000 / CGP 2022 Part II.B / CABQ Fugitive Dust Program
Trackout control mats are engineered interlocking pads used at construction entrances to remove soil from vehicle tires before they reach public roadways. Inspections Plus sells, rents, and installs Trackout Control mats throughout New Mexico and Arizona.
NM-Specific Requirements
·CABQ requires trackout prevention at all construction entrances in Bernalillo County. Trackout Control mats satisfy this requirement and are preferred by CABQ air quality inspectors over loose aggregate pads.
·Trackout Control mats are SWPPP-compliant and reusable — they can be cleaned in place and relocated to new entrances during construction phasing.
·Caliche-heavy sites: Trackout Control mats are more effective than aggregate stabilized pads on sites with fine caliche dust because the mat structure traps particles, while aggregate pads simply provide a walking surface.
·Trackout Control mats are available for sale or rental through Inspections Plus. Rental requires 10-day minimum advance notice for delivery scheduling.
Installation Steps
1Install at all construction entrance/exit points used by tracked or tired equipment
2Minimum mat length: 50 feet (longer for larger equipment)
3Anchor mat with stakes or rebar pins at corners and midpoints
4Post SWPPP signage identifying the mat as a permitted BMP
Inspection & Maintenance
Inspect after heavy equipment use — mat should be free of excessive mud accumulation
High-pressure wash when sediment accumulation reduces effectiveness
Inspect anchor stakes after storm events — saturated soil can allow mat migration
At project completion: clean, inspect, and return (rental) or relocate/remove (sale)
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