Why grading and drainage is needed in Keyes
Grading and drainage here starts from the assumption that the site holds its own water. The County's reviews of recent Keyes projects describe storm water kept on the parcel: a five-acre Rohde Road site draining to a storm drain basin, and an earlier Nunes Road proposal with a basin of about an acre. A basin, a swale or a dry well on the property is the design, so its depth, its inlets and the fall of the ground feeding it are the whole of the drainage system.
The community-wide storm project was drawn in 2008 and covered 235 acres. Filed with cross streets at Anna and Grace Avenues, 10th Street, Nunes and Motsinger Roads, it described a new detention basin, improvements to the existing basin including a pumping station, a collection system and full-width street improvements with curbs and gutters. A property owner cannot rely on any particular street being served, so the parcel is surveyed for what it can do by itself.
The soils drain, but not quickly. Mapping at the Rohde Road site returns 55 percent Hanford sandy loam and 45 percent Tujunga loamy sand, and along Golden State Boulevard south of Keyes Road it gives Hanford sandy loam on nought to three percent slopes and Dinuba sandy loam on nought to one, the Dinuba described as moderately well drained with slow permeability and very slow runoff. Very slow runoff on nearly level ground is a description of standing water, and the building code answers it with a measured fall away from the wall rather than with a larger pipe.
Three weeks of rain can deliver two thirds of a normal year. At the Turlock number two normals station, which covers Keyes, the 22 days from 26 December 2022 to 16 January 2023 brought 8.43 inches against a yearly normal of 12.39, with four separate days near or above an inch. Any on-site basin that is silted, or any inlet that is blocked, gives up in the second week of a run like that rather than the first.
The laterals that edge the town are open only in winter. Turlock Irrigation District's Upper Lateral 2½ forms the north edge of the community plan area and runs along the north side of the Rohde Road site in a 70-foot right of way, and the district allows work on its irrigation facilities only in the non-irrigation season, typically 1 November to 1 March. That window is the opposite of the dry months earthwork wants, so the two parts of a job near a lateral are often planned separately.
From 26 December 2022 to 16 January 2023 the Turlock number two gauge that covers Keyes recorded 8.43 inches, about two thirds of a normal year's rain, in 22 days. A basin sized for one storm meets four of them in a run like that.
Grading and drainage, as delivered in Keyes
Keyes is eight road miles south of the Modesto base by Highway 99 to the Keyes Road interchange. Every job leaves the same record: levels before and after, photographs of each drain before backfill, and the water test.
The contractor assigned to the request walks the parcel, and wet weather is the useful weather for it. Site visit scheduled at a time that suits you. Start date set in the written estimate. Where water lies, how much fall there is at each wall, the depth and silt line of any on-site basin and the point the site discharges to are all measured and photographed.
The planned excavation is delineated in white first, the notification center receives at least two working days' and at most fourteen calendar days' notice, and no earth moves until every operator named on the ticket has responded. An installation classed high priority within ten feet is met on site by its operator, and the ticket is renewed by its 28th day.
Keyes is unincorporated, so permits come from the Stanislaus County Building Permits Division, which also decides at application whether a soils test is required. Plans are the owner's.
A trench of five feet or more takes a protective system, spoil is kept two feet back from the edge, and nothing undermines paving without support under it.
Unsuitable ground is stripped, fill is placed in lifts and compacted with no organics and no rock over twelve inches in it, and the backfill at a foundation allows for the settlement to come. The finished surface is then cut to falls that carry water all the way to the basin or the inlet.
Clean stone, filter fabric and bedded pipe make the drain, and the discharge goes by gravity or pump to a point the County accepts.
The finished falls are surveyed, the new drains are run with water, bare ground is stabilised, and the County building official signs the job off before the grades and photographs go to the owner.
Where grading and drainage is needed in Keyes
Keyes is an 1871 rail siding, a freeway bypass and half a century of separate additions, and the ground drains differently on each side of them.
7th Street community core
The pedestrian-oriented spine of residential, commercial and public uses, with the community services district office and a fire station rated in poor condition. The core was laid out long before the community had a collection system, so a frontage here drains across its own ground to whatever the street offers.
Original townsite beside the Union Pacific line
Laid out at right angles to the northwest-southeast railroad in 1871 and offset from the later north-south grid, with around 300 homes across the community predating 1950. A skewed block meets the newer grid at an angle, so the direction water wants to run and the direction the street falls are rarely the same.
SR 99 and Keyes Road interchange, Highway Commercial
The community's gateway, with highway commercial land at the interchange, Golden State Boulevard and Keyes Road, and about 122,000 vehicles a day on the freeway. Fuel canopies, car washes and retail shells filed here have each carried their own on-site storm basins rather than a connection to a public line.
Golden State Boulevard, Nunes Road to East Keyes Road
Planned development land for highway commercial uses, including a truck terminal approved in 2022 with a maintenance shop, an administrative building and a truck dock. A 2015 study of a Nunes Road site found remnant foundations and a drainage basin left by a former trucking business, which is what old yard ground usually holds.
Golden State Boulevard, East Keyes Road to Barnhart Road
65 acres with a truck center, a food distribution operation, a service station and a large storage facility built or under construction, where the district proposed extending its sphere to match the community plan boundary. Soils here are Hanford and Dinuba sandy loams and the area is mapped outside the 0.2 percent floodplain.
Rohde Road gateway and TID Upper Lateral 2½
A five-acre site with 39,393 square feet of mini-storage in thirteen buildings, a duplex, a fourplex and a converted house, with the district's Upper Lateral 2½ along its north side in a 70-foot right of way. Buildings put up without the required permits leave grading nobody has ever measured.
Industrial lands west of SR 99 and Foote Road
84 acres of industrial and 40 of planned industrial land with direct heavy rail access, buffered from the residential side east of the freeway, and the district's lift station on Foote Road. Rail-served yards are worked on compacted aggregate, and the fall across them has to be surveyed rather than seen.
Norma Way, Nunes Road and Washington Road subdivisions
Newer housing to the north and east on 5,000 square foot minimum lots, built on land annexed for homes and a school. Small lots leave little ground between a wall and a fence, which is exactly the case the code answers with a swale where ten feet of fall cannot be had.
Anna Avenue, Grace Avenue and 10th Street
The community's multifamily district and the cross streets of the 2008 County storm drain project, along with a 2019 filing to replace wood street light poles on 10th Street with new pavement, curb, gutter and sidewalk. New curb sets a fixed level that the parking courts behind it have to be graded to meet.
Hatch Park, Maud Avenue and Lucinda Avenue civic blocks
The community's park, the County library on Maud Avenue and a community center and parking lot the County applied in 2025 to renovate on a 4.48-acre parcel. Turf and parking on one site drain at completely different rates, and the junction between the two is where water collects.
Mobile home parks on the district edge
Scattered urban uses in and around the district sphere running on their own sewer and water, with 257 mobile homes counted across the community. Coach rows drain along long, nearly level aisles into very few inlets, so one lost inlet puts standing water under several homes at a time.
East Keyes Road farm edge and the Ceres Main Canal
Almond ground and canal crossings, where the district's Ceres Main Canal meets Lower Lateral 3 and a County bridge over the canal was replaced with wider lanes and shoulders. Farm parcels turning into built sites need a pad, a fall and a basin before anything else happens on them.
Grading and drainage sub-services available in Keyes
Questions from Keyes property owners and managers
Usually nowhere off the property. County reviews of recent Keyes projects describe storm water held on site, in a storm drain basin on a five-acre Rohde Road parcel and in a basin of about an acre proposed on Nunes Road. The 2008 community storm drain project set out a new detention basin, a pumping station and a collection system across 235 acres, but a particular street cannot be assumed to be served, so the parcel is surveyed for what it can hold itself.
Keyes is unincorporated, so building and grading permits come from the Stanislaus County Building Permits Division rather than from a city, and the community services district has no land use authority. The County has recorded that flood zone requirements are handled through the building permit process and that a soils test may be required when the permit is applied for. Plans and any report come from the owner, and the work is built to them.
In winter. The district allows work on its irrigation facilities only during the non-irrigation season, which typically runs from 1 November to 1 March and can vary, and the lateral along the north side of the Rohde Road site sits in a 70-foot right of way. Work touching a district facility is arranged with the district on its own terms, and no private drain can be promised a connection into a lateral.
Because sandy is not the same as fast. Mapping along Golden State Boulevard south of Keyes Road returns Dinuba sandy loam described as moderately well drained with slow permeability and very slow runoff, alongside Hanford sandy loam on slopes of nought to three percent. Very slow runoff on almost level ground means water waits rather than travels, so the correction is a measured fall and a defined low point rather than a hope that it will soak away.
Three separate County site studies in Keyes, on Rohde Road, on Nunes Road and along Golden State Boulevard, each placed their site in Zone X, outside the 0.2 percent floodplain, but a zone is read for an address rather than for a community. Where a site does fall inside a flood hazard area, grading and fill are approved only where the fill is placed, compacted and sloped to resist shifting, slumping and erosion, and floodways take none.
The building code sets a minimum slope for the ground immediately next to a foundation over a set distance, with a lower minimum for a swale and for impervious surfaces inside that band, and it allows a reduced figure where climatic or soil conditions warrant. Where a lot line, a wall or another obstruction leaves no room, a swale or another approved method of diverting water away from the foundation is accepted instead.
Grading and drainage near Keyes
