Facility Overview
Granite Rock Company Redwood City is operating under a active permit of type: Industrial. Primary industry: Ready. Secondary industry: Asphalt Paving Mixtures and Blocks. Tertiary industry: Scrap and Waste Materials.
The site has self-reported imperviousness of 70%. In the context of the Industrial General Permit for stormwater runoff, imperviousness refers to the percentage of the facility's surface area that doesn't allow water to penetrate, such as concrete, asphalt, or rooftops. The higher the imperviousness percentage, the more potential impact on local water quality as there is a greater surface area to accumulate pollutants.
In terms of water impact, this facility indirectly affects the Steinberger Creek. This information is crucial for understanding the facility's potential environmental influence on local water resources.
Additional Details
Historical Exceedances
This facility has historically exceeded limits for the following parameters:
pH
pH levels outside the normal range can harm aquatic life and affect water chemistry. Acidic water can leach toxic metals from sediments, while alkaline water can increase ammonia toxicity.
Iron, Total
Excessive iron can harm aquatic ecosystems by forming precipitates that smother habitats. It can also affect fish gills and reduce visibility in water.
Oil and Grease
Oil and grease can form films on water surfaces, reducing oxygen levels and harming aquatic life. They can also contaminate sediments and be toxic to organisms.
Total Suspended Solids (TSS)
High levels of suspended solids can reduce water clarity, harm fish gills, smother aquatic habitat and eggs, and transport pollutants through water bodies.
These limits reflect Water Quality Standards promulgated to protect human health or the environment, or standards that the State or EPA developed to indicate the Facility may be failing to implement best practices to protect storm water.
Discharge Reports Summary
| Year | Sample Reports | Exceedances | Status |
|---|---|---|---|
| 2024 | 6 | 8 | Exceedances Detected |
| 2023 | 5 | 6 | Exceedances Detected |
| 2022 | 5 | 2 | Exceedances Detected |
| 2021 | 6 | 5 | Exceedances Detected |
| 2020 | 6 | 3 | Exceedances Detected |
| 2019 | 5 | 6 | Exceedances Detected |
| 2018 | 14 | 22 | Exceedances Detected |
| 2017 | 8 | 11 | Exceedances Detected |
| 2016 | 6 | 10 | Exceedances Detected |
Discharge Report Exceedances Trend
This chart shows the trend of discharge report exceedances over time. The values represent the number of exceedances for each year.