Bioslope Media Mixture

Bioslope Media Mixture

Bioslope Soil Media, Bio-slope Planting Media, Erosion Control Soils, GDOT Bioslope Media, Urban Street and Landscape Soil, Engineered Soil Media, GDOT Engineered Soil Mix, State DOT Soil, Engineered Topsoil, Engineered Soil, Infiltration Trench, Sand Filter, Organic Filter, Engineered Topsoil


Bioslopes, Bioslope Planting Media, Best Management Practices (BMPs), Erosion Control Soils, GDOT Bioslope, Urban Street and Landscape Soil, Vegetated Filter Strip, Water Quality Filter Strips, Airports, Roadways, Embankments, Water Quality Improvement, Stream Channel Protection

Key Benefits

Custom blended sand, soil, gravel, or other amendments to your soil specifications to meet project parameters such as pH, soil texture, cation exchange capacity (CEC), total suspended solids (TSS), phosphorus index (p-Index), soluble salts (SS), Infiltration (ksat in in/hr or in/day), nutrient value, metals, or other specifications; Storm water filtration and management, Improves water quality, Promotes healthy plant growth for nutrient update; Reduces compaction; Removes pollutants; Retains water and nutrients for plants


Screened, blended to meet the target initial infiltration rate of a min 50 in/hr (saturated hydraulic conductivity, kSat) or percolation rate, Horticultural grade perlite to grade specifications; USDA soil class texture; Adjusted pH for with dolomite and gypsum; All-natural soil with no toxicity

Bioslope Media Mixture

Bioslope Media Mixture is the specialized media used for filtration within a BMP called a bioslope.  Bioslopes are a longitudinal slope that typically run parallel with a highway, airport runway, or parking lot to capture and treat runoff from a site.  A filter strip, usually grassed between the pavement or impervious surface usually separates it from the bioslope to reduce flow and filter the runoff.  Pollutant removal includes total suspended solids (TSS), metals (cadmium, copper, lead, zinc), nutrients (nitrogen and phosphorus), and pathogens (fecal coliform).  Bioslopes also reduce runoff volume, and therefore provide channel and flood protection for streams in the watershed.

The bioslope soil mix overlays an underdrain system.  It is at a minimum depth of 12”.  The Bioslope Media Mixture is a blend of crushed rock, dolomite, gypsum, and perlite.  The initial infiltration rate of this mixture is 50+ in/hr and will reduce as it filters water over time.  The primary component is the gravel with the perlite being the secondary component.  Dolomite and gypsum are blended based on the amount of perlite by the pound (lb).  All the materials must achieve the specified gradation and by free of any toxic materials (horticultural grade).

River Sand, Inc. has supplied bulk bioslope media mixture for many projects in and around Atlanta.  Our in-house laboratory can meet the specs and assure quality control.  We can arrange for FOB price or provided a delivered quote for the cost of Bioslope Media Mixture delivered to your project.

We Deliver!

River Sand, Inc. is your bulk landscaping supplier and source for construction materials including sand, soil, and gravel. Call today for a quote and to schedule delivery for your Bioslope Soil Media Mixture.

Frequently Asked Questions

Do you have questions about Bioslope Media Mixture? We have answers!

According to the Georgia Stormwater Manual (, “Bioslopes (also referred to as ecology embankments) are water quality best management practices that use a permeable engineered soil media to capture and treat stormwater runoff from adjacent paved areas.  Bioslopes are typically installed along embankments or other slopes and designed to treat sheet flow stormwater runoff.

Bioslopes are designed with limited longitudinal slopes to force the flow to be slow and uniform, thus allowing for particulates to settle and limiting the effects of erosion. Once infiltrated into the highly permeable engineered soil layer, an underdrain is typically used to remove the treated stormwater from the embankment or slope. Larger flow rates, from less frequent storm events, in the form of sheet flow bypass the engineered soil media by overtopping and continuing down the embankment or slope.

Usually, bioslopes are installed parallel to roads and right of ways just off the shoulder.  They are useful as stormwater management practices when the downslope area is limited in space to treat stormwater with other practices such as bioswales or bioretention basins.  GDOT (Georgia Department of Transportation) projects, county, and city municipalities include bioslopes as part of their design plan.

Aggregate and soil suppliers, like River Sand, Inc., have facilities and stockpiles of materials to blend bioslope media.  Most small landscaping yards do not blend products or have the capability to blend accurately.  Many large rock or stone quarries only provide aggregates and not engineered soil blends or the QA/QC protocols to back them up.

Bio-slopes are designed to treat sheet flow from adjacent impervious surfaces such as roads. Stormwater sheet flow moves off of the roadway, sometimes through another filter treatment, over a bio-slope. Runoff is filtered through the bio-slope and the bio-slope media. The bio-slope media is composed a combination of coarse aggregate and permeable soil particles with high water retention capability. Bioslope mix may include aggregates, perlite, dolomite, and gypsum. The dolomite and gypsum components help treat stormwater and act as a buffer for acidic pH conditions and provide treatment for heavy metals. Perlite aids in the treatment of particulates, metals, and nutrients with it primary function being to retain moisture.  Treated runoff exits the bioslope system through a granular drain backfill material and sometimes with a perforated drain pipe. The overall effect filters stormwater to reduce the amount of runoff and improve water quality from runoff. 

Bioslope media or bioslope mix is best purchased by the loose, bulk ton and delivered in a dump truck or dump trailer.  Planning is critical to either place the material into the system directly or store in a manner (i.e. on concrete/asphalt) to prevent contaminants from being mixed with the bioslope media prior to installation.

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