OAR 340-071-0265
Capping Fills

(1) Criteria for approval. Each site approved for a capping fill system must meet all the following conditions:
(a) Slope does not exceed 12 percent.
(b) Temporary water table is not closer than 18 inches to the ground surface at any time during the year. A 6-inch minimum separation must be maintained between the bottom of the absorption trench and the temporary water table.
(c) Where a permanent water table is present, a minimum 4-foot separation must be maintained between the bottom of the absorption trench and the water table.
(d) Except as provided in subsection (e) of this section, where material with rapid or very rapid permeability is present, a minimum 18-inch separation must be maintained between the bottom of the absorption trench and soil with rapid or very rapid permeability.
(e) Sites may be approved with no separation between the bottom of the absorption trenches and soil with rapid or very rapid permeability (as defined in OAR 340-071-0100 (Definitions)(148)(a) or (b)), and absorption trenches may be placed into such soil if any of the following conditions occur.
(A) A confining layer occurs between the bottom of absorption trenches and the temporary groundwater table and a minimum 6-inch separation is maintained between the bottom of absorption trenches and the top of the confining layer.
(B) A layer of non-gravelly (less than 15 percent gravel) soil with sandy loam or finer texture at least 18 inches thick occurs between the bottom of the absorption trenches and the groundwater table.
(C) The projected daily sewage flow does not exceed a loading rate of 450 gallons per acre per day.
(f) Effective soil depth is 18 inches or more below the natural soil surface.
(g) Soil texture from the ground surface to the layer that limits effective soil depth is no finer than silty clay loam.
(h) A minimum 6-inch separation is maintained between the bottom of the absorption trench and the layer that limits effective soil depth.
(i) The system can be sized according to effective soil depth in Table 4. [NOTE: All tables are found in OAR 340-071-0800 (Tables).]
(2) Installation requirements. The cap must be constructed as the permit requires. Unless the agent requires otherwise, construction must follow this sequence:
(a) The agent must examine and approve the soil before placing the cap. The texture of the soil used for the cap must be the same textural class as or one textural class finer than the natural topsoil unless otherwise allowed in this division.
(b) Capping fills must be constructed between June 1 and October 1 unless the agent allows otherwise. The upper 18 inches of natural soil must not be saturated or have a moisture content that causes loss of soil structure and porosity when worked.
(c) The absorption area and the borrow site must be scarified to destroy the vegetative mat.
(d) The system must be installed as specified in the construction-installation permit with a minimum 10-foot separation between the edge of the fill and the absorption facility.
(e) Filter fabric must be used between the drain media and the soil cap, unless the agent authorizes otherwise.
(f) Fill must be applied to the fill site and worked in so that the two contact layers, native soil and fill, are mixed. Fill material must be evenly graded to a final depth of 10 inches over the drain media for an equal system or 16 inches over the drain media for a serial system to allow for appropriate settled depths. Both initial cap and repair cap may be constructed at the same time.
(g) The site must be landscaped according to permit conditions and be protected from livestock, automotive traffic, and other activity that could damage the system.
(3) Required inspections. Unless the agent waives it, the following inspections must be performed for each capping fill installed.
(a) Inspecting both the absorption area and borrow material before cap construction for scarification, soil texture, and moisture content.
(b) Inspecting the installed absorption facility before covering.
(c) Inspection after the cap is placed to determine adequate contact between fill material and native soil (no obvious contact zone visible), adequate depth of material, and uniform distribution of fill material.
(d) Final inspection after landscaping or other erosion control measures are established.
[NOTE: All tables are found in OAR 340-071-0800 (Tables).]

Source: Rule 340-071-0265 — Capping Fills, https://secure.­sos.­state.­or.­us/oard/view.­action?ruleNumber=340-071-0265.

340‑071‑0100
Definitions 340‑071‑0110
Purpose 340‑071‑0115
Technical Review Committee 340‑071‑0120
Jurisdiction and Policy 340‑071‑0130
General Standards, Prohibitions and Requirements 340‑071‑0135
Approval of New or Innovative Technologies, Materials, or Designs for Onsite Systems 340‑071‑0140
Onsite System Fees 340‑071‑0150
Site Evaluation Procedures 340‑071‑0155
Existing System Evaluation Report 340‑071‑0160
Permit Application Procedures — Construction, Installation, Alteration, and Repair Permits 340‑071‑0162
Permit Application Procedures — WPCF Permits 340‑071‑0165
Permit Denial Review — Construction-Installation, Repair, Alteration Permits 340‑071‑0170
Pre-Cover Inspections 340‑071‑0175
Certificate of Satisfactory Completion 340‑071‑0185
Decommissioning of Systems 340‑071‑0200
Prior Construction Permits or Approvals 340‑071‑0205
Authorization to Use Existing Systems 340‑071‑0210
Alteration of Existing Onsite Wastewater Treatment Systems 340‑071‑0215
Repair of Existing Systems 340‑071‑0220
Standard Subsurface Systems 340‑071‑0260
Alternative Systems, General 340‑071‑0265
Capping Fills 340‑071‑0275
Pressurized Distribution Systems 340‑071‑0280
Seepage Trench System 340‑071‑0285
Redundant Systems 340‑071‑0290
Conventional Sand Filter Systems 340‑071‑0295
Conventional Sand Filter Design and Construction 340‑071‑0302
Recirculating Gravel Filter (RGF) 340‑071‑0310
Steep Slope Systems 340‑071‑0315
Tile Dewatering System 340‑071‑0320
Split Waste Method 340‑071‑0325
Gray Water Waste Disposal Sumps 340‑071‑0330
Nonwater-Carried Systems 340‑071‑0335
Cesspools and Seepage Pits 340‑071‑0340
Holding Tanks 340‑071‑0345
Alternative Treatment Technologies (ATTs) 340‑071‑0360
Absorption Trenches in Saprolite 340‑071‑0400
Geographic Area Special Considerations. 340‑071‑0410
Rural Area Consideration 340‑071‑0415
For Cause Variances 340‑071‑0420
Hardship Variances 340‑071‑0425
Variance Officers 340‑071‑0430
Variance Hearings and Decisions 340‑071‑0435
Variance Permit Issuance, Inspections, Certificate of Satisfactory Completion 340‑071‑0440
Variance Appeals 340‑071‑0445
Variance Administrative Review 340‑071‑0460
Moratorium Areas 340‑071‑0500
Community Systems 340‑071‑0520
Large Systems 340‑071‑0600
Sewage Disposal Service Licenses 340‑071‑0650
Training and Certification Requirements for System Installers and Maintenance Providers 340‑071‑0800
Tables
Last Updated

Jun. 8, 2021

Rule 340-071-0265’s source at or​.us