Retention Ponds, French Drains, and Detention Basins in Placer County
Does your Granite Bay property pool water after every rain? Many Placer County hillside lots collect runoff at low points and against foundations. The soil cannot absorb fast enough. Water backs up against garage doors, saturates retaining walls, and erodes fresh graded areas. For large estate lots and rural parcels, this is not just an inconvenience. Unmanaged stormwater causes structural damage over years and creates Placer County NPDES permit violations on newly graded projects.
We excavate detention basins that capture stormwater surge and release it slowly within 48 hours. We also install French drain systems to move subsurface water away from your foundation before it pools. Also, we grade vegetated swales and install culverts under driveways for long-term surface runoff control.
Ready to fix your drainage problem? Call Pina Excavating at (916) 415-3157 or use our free Drainage Pond Cost Calculator to estimate your project before you meet with a civil engineer.
- CSLB Licensed #268555
- 50+ Years
- Granite Bay & Placer County
- 5 Star Service
Retention Pond Excavation
A retention pond holds water permanently. It acts as a reservoir on large lots, collecting runoff, recharging groundwater, and providing a water source for irrigation or livestock. Placer County’s clay-rich soil holds water naturally in many areas without a pond liner, which reduces installation cost.
We excavate retention ponds from 6 to 15 feet deep depending on your site and water volume requirements. We shape the walls, grade an inlet channel, and cut an emergency overflow spillway so the pond does not overtop your embankment during heavy rainfall.
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Detention Basin Excavation
A detention basin captures stormwater surge during heavy rain and releases it slowly. The basin drains dry within 24 to 48 hours. Placer County requires detention basins for new construction projects that increase impervious surface area, including roofs, driveways, and parking lots.
Your civil engineer sizes the basin based on your drainage area and the storm event the county requires (10-year, 25-year, or 100-year). We execute the excavation to those exact specifications. We also grade the outlet structure and side slopes to match your engineer’s drainage report.
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French Drain Installation
A French drain is the most common fix for Granite Bay’s most common drainage problem. Subsurface water moves downhill through clay soil and saturates foundations, retaining walls, and basement slabs. A French drain intercepts that water before it reaches your structure.
We trench at 24 to 48 inches deep, install perforated pipe in a gravel bed, wrap it in filter fabric, and run the pipe to a daylighted outlet or storm drain connection. This moves subsurface water away from your foundation without disturbing your landscaping on the surface.
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Vegetated Swale Grading
A swale is a shallow, open drainage channel with a planted surface. It moves runoff across your property at a controlled slope, slowing water velocity and allowing partial absorption into the soil. Swales cost less to maintain than concrete drainage channels and qualify as Low Impact Development (LID) stormwater controls under Placer County’s LID ordinance.
We grade the swale channel to the correct slope and cross-section, locate check dam positions for flow control, and prepare the inlet and outlet transitions. We coordinate with your landscaper for the final vegetative cover.
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Culvert Pipe Installation
Culverts let surface water pass under driveways, roads, and access paths without pooling or washing out the road base. We size culverts based on the drainage area above the crossing and install them with a correct fall for gravity flow.
We work with corrugated metal pipe (CMP) and high-density polyethylene (HDPE) culverts. Each installation includes formed inlet and outlet wingwalls or headwalls and a compacted structural fill over the pipe so the road surface does not depress over time.
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Placer County Stormwater and NPDES Requirements
Property owners and developers who disturb more than one acre of land in Placer County must obtain a Construction General Permit (CGP) under the NPDES program. This permit requires a Stormwater Pollution Prevention Plan (SWPPP) and may require on-site detention or retention facilities.
| Trigger | Requirement |
|---|---|
| Land disturbance over 1 acre | NPDES Construction General Permit (CGP) from State Water Board |
| New impervious surface, any size | Placer County Low Impact Development (LID) compliance |
| Detention basin required in drainage report | Must be excavated to civil engineer specifications |
| Projects within 100 feet of a stream or creek | May require CDFW Streambed Alteration Agreement |
Pina Excavating does not prepare SWPPP documents or engineer drainage reports. We execute the excavation and grading work specified in those reports with the equipment and crew experience that full compliance requires.
Agricultural Stock Ponds and Ranch Water Reservoirs
Ranch and farm properties in Loomis, Newcastle, Penryn, and Yuba County often need stock ponds for livestock water, orchard irrigation, and wildlife habitat. Placer County’s clay-heavy soils hold water without a pond liner when clay content exceeds 20 percent, which reduces installation cost compared to sandy-soil regions.
We excavate stock ponds from 6 to 12 feet deep and grade the earthen dam with a 3:1 side slope and a compacted crown. We cut an emergency spillway on the low end of the dam so the pond does not overtop during heavy rainfall. If your project involves diverting from a creek or seasonal waterway, we can advise on State Water Board notification requirements.
Drainage and Pond Service Areas
We serve the full Placer County corridor from Granite Bay to the Sierra foothills. Our crews regularly work in:
Contact Us Today:
- (916) 740-7992
- mikepinaemail@yahoo.com
- Granite Bay & Placer County
Our Service Areas in Granite Bay & Placer County:
- Granite Bay
- Roseville
- Rocklin
- Lincoln
- Auburn
- Loomis
- Newcastle
- Penryn
- Folsom
- El Dorado Hills
- Citrus Heights
- Weimar
- Marysville
- Olivehurst
- Yuba City
Stop Guessing. Fix Your Drainage Problem the Right Way.
Call Pina Excavating today for a free on-site drainage assessment at your Granite Bay or Placer County property. We walk your lot, assess site conditions, and give you an honest estimate before you commit to anything.
Frequently Asked Questions
What is the difference between a retention pond and a detention basin?
A retention pond holds water permanently. It always has standing water and acts as a reservoir. A detention basin captures stormwater surge and drains completely within 24 to 48 hours. The right type depends on your goals and Placer County permit requirements.
Do I need a permit to build a drainage pond or French drain in Placer County?
French drains on residential lots typically do not require a permit. Detention basins and grading projects over one acre require a Placer County Grading Permit and may trigger NPDES Construction General Permit requirements. We advise on permit thresholds during your free estimate.
Does my Granite Bay hillside lot need a French drain?
If you have water pooling against your foundation, wet garage floors after rain, or soft saturated soil near retaining walls, a French drain is very likely the right fix. We assess your drainage during every free site visit.
Can you excavate a stock pond on a Loomis or Newcastle ranch?
Yes. We excavate agricultural stock ponds in Placer County and Yuba County. Clay-rich soils in this region often hold water without a liner, which reduces cost. We advise on State Water Board notification if your project involves a stream diversion.
What size detention basin do I need to comply with Placer County stormwater rules?
A licensed civil engineer sizes your detention basin based on your drainage area, impervious surface, and the design storm event required by Placer County (typically the 10-year or 100-year storm). We execute the excavation to those engineered specifications.