Services

Our most popular services include soil infiltration rate evaluations, prescriptive stormwater plans, critical area assessments for geologically hazardous areas (erosion, landslide, coal mine and tsunami hazards), and property purchase feasibility assessments for new construction and redevelopment projects. 

We specialize in residential development, including single-family residences, infill and middle housing (duplexes, townhouses, and cottage housing), accessory dwelling units (ADUs and DADUs), home additions, detached buildings, and small subdivisions. 

Our typical services are as detailed below:   

Stormwater

• Soil Infiltration Evaluations: We can determine the infiltration rates of the native soil in accordance with the current Stormwater Management Manual for Western Washington using the soil grain size analysis or pilot infiltration testing methods. The results are presented in a site characterization report that can be used by a civil engineer for the design of on-site stormwater management facilities. The soil infiltration testing can also be used for determining saturated hydraulic conductivity (Ksat) of native soil or for determining the feasibility of permeable pavement, rain gardens/bioretention, and other stormwater infiltration facilities.

• Soil Reports for Roof Downspout Infiltration Trenches & Drywells: We can prepare a soil report that references a sufficient number of soil logs that is used to determine if the native soils are suitable for roof downspout full infiltration trench or drywell systems in accordance with BMP T5.10A.

• Prescriptive Stormwater Layout Services for Residential Projects: We offer prescriptive stormwater planning and layout services for residential projects that are required to meet On-site Stormwater Management Minimum Requirements No. 1-5. This typically includes preparing the required soils report and prescriptive stormwater site plan layouts. The stormwater layout considers the feasibility of on-site stormwater management facilities such as downspout full infiltration systems (BMP T5.10A), rain gardens and bioretention, downspout dispersion systems (BMP T5.10B), perforated stub-out connections (BMP T5.10C), permeable pavement (BMP T5.15), concentrated flow dispersion (BMP T5.11), sheet flow dispersion (BMP T5.12), and post-construction soil quality and depth (BMP T5.13).

• Off-Site & Alternative Stormwater Connections: For residential projects where the above-mentioned on-site stormwater management BMPs are determined to be not feasible, we can provide recommendations for the following options, as applicable: a connection to a ditch or stormwater main in the right-of-way; a connection to the curb and gutter using a residential sidewalk drain; a connection to a ditch or stormwater main using a sump-pumping system; and in some cases where erosion is a concern, we may be able to recommend a configuration for a high density polyethylene (HDPE) stormwater outfall or tightline system with a diffuser tee for energy dissipation.   

• Full Dispersion: We offer prescriptive stormwater planning and layout services for residential projects that qualify for Full Dispersion in accordance with BMP T5.30. This option is typically not feasible for properties that are less than 5 acres in size, sites with steep topography, or properties that are encumbered by critical areas and buffers.  

• Sudden Valley Homeowner Stormwater Workbook: We can prepare soils reports and provide prescriptive stormwater plans for residential projects that qualify for the Sudden Valley Community Association Appendix D: Homeowner Stormwater Workbook (including Stormwater Facility Location Site Plans and Tree Canopy Retention Plans).

• Soil Reports for Watersheds: We frequently prepare soil infiltration reports and provide prescriptive stormwater site plan layouts for residential projects that are located in the Lake Whatcom, Lake Samish, Lake Padden, Birch Bay and Drayton Harbor watersheds, as well as NPDES Phase 2 areas.  

• High Groundwater Determination: We can conduct wet season groundwater monitoring to help estimate the depth to seasonal high groundwater. Other indicators, such as soil mottling and the presence of consolidated soil can also help us determine the depth to high groundwater or a restrictive layer.

• Cation Exchange Capacity & Organic Content Testing: We offer help with cation exchange capacity (CEC) and organic content (OC) testing to assess if the native soil is suitable for the treatment of pollution generating surfaces. 

• Stormwater Pollution Prevention Plans: We can help with Construction Stormwater Pollution Prevention Plans (SWPPP) for residential projects that are required to meet Minimum Requirements No. 1-5. This includes help with filling out Whatcom County's Small Construction Site Stormwater Erosion and Sedimentation Control Plan Template form.

Note: Sound Geology, LLC provides professional geological evaluations and documentation for prescriptive stormwater planning, and does not provide civil, structural, or geotechnical engineering design services requiring a Professional Engineer (PE) stamp.

Geologically Hazardous Areas

• Landslide & Erosion Hazard Evaluations: We offer critical area evaluations for erosion and landslide hazard areas for residential projects in the City of Bellingham and Whatcom County. The evaluations can include: a slope stability assessment; a coastal erosion rate estimate (bluff retreat); a safe building setback determination from the top or toe of a slope; determination of a suitable setback to allow for a 100-year design life without the need for shoreline armoring; recommendations for vegetation management on slopes; stormwater management and drainage control recommendations; and identification of native soil and bedrock layers that are suitable for foundation support. We can also provide limited evaluations for smaller projects that qualify for minor critical area permits in the City of Bellingham. 

• Tsunami Hazard Area Evaluations: We can provide tsunami hazard area evaluations when required for residential projects that are located within the low-lying coastal areas of Birch Bay, Blaine, Ferndale and Sandy Point. This type of evaluation includes estimating inundation depths and current speeds resulting from a tsunami that can be used for structural mitigation, if needed.

• Coal Mine Hazard Assessments: We offer coal mine hazard assessments for residential projects in the City of Bellingham. Most of the projects that we work on are for new single-family homes, townhouses, duplexes, accessory dwelling units (ADUs) and subdivisions that are located above or within close proximity to the Bellingham No. 1 coal mine. 

Additional Services

• Subsurface Investigations for Residential Foundations: We also offer services that can be helpful for planning a residential project. Such services can include: identifying soil and material classes for correlating applicable load-bearing pressures and lateral soil loads per the International Residential Code; uncontrolled fill and peat delineation; and depth to competent bedrock investigations.

• Drafting Services: We provide limited drafting services using AutoCAD for simple site plans, critical area maps, subsurface cross-sections, stormwater site plans, tree canopy retention plans, and erosion control plans. 

• Permits: We can help with geological documentation for residential stormwater permits, critical area permits, and shoreline exemption permits. 

• Referrals: We can also provide referrals for qualified local professionals (wetland biologists, civil/structural/geotechnical professional engineers, house and building designers, archaeologists, land use and development consultants, permit specialists, septic designers and contractors).