A community group and another residential development company say they want ample time to discuss their concerns about D.R. Horton-Schuler Homes' large-scale Ho'opili project before the state Land Use Commission.

Horton is seeking to reclassify 1,554 acres on the 'Ewa Plain from agricultural to urban use for the Ho'opili project, which is projected to have up to 11,500 homes, as well as commercial and business space, schools and other amenities.

In separate filings, Friends of Makakilo and Haseko (Ewa) Inc. have filed to become intervenors in Horton's petition, arguing that their issues cannot be adequately addressed otherwise.

Sandwiched between 'Ewa, Kapolei, Makakilo, Kunia and Waipahu, the planned project "may be the single largest classification request ever made for the island of O'ahu," according to the state Office of Planning.

The development has been compared in size to Mililani and Hawai'i Kai.

If granted intervenor status, the parties would be able to do more than simply testify about their concerns. They would be allowed to cross-examine the developer and its witnesses, and also be given ample time to present their own cases and witnesses.

The commission is expected to decide whether to grant the two parties' requests during its two-day meeting on the Big Island today and tomorrow. Horton's petition itself is now expected to be heard in Honolulu in March.

Friends of Makakilo is arguing that Ho'opili would contribute to urban sprawl, overtax the area's roads and other infrastructure, and eliminate valuable agricultural lands and green space.

If the project is allowed to be developed, "from Hawai'i Kai to Ko Olina there will be a continuous urban sprawl," the petition for intervention said.

Haseko's concern is more focused. Part of the planned Ho'opili project lies within the Kalo'i Gulch drainage basin. Haseko's Hoakalei and Ocean Pointe projects are downstream, at the bottom of the basin.

As a result, "Ho'opili's flood control and drainage infrastructure could have significant impacts on Haseko's development," Haseko's petition for intervention said.

Michael T. Jones, Horton's Schuler division president, said no new runoff from Ho'opili would be allowed into the gulch through the Haseko property.

Most runoff generated by development would be kept on site, Jones said. A small portion would be accepted on the Department of Hawaiian Home Lands housing project, but would not get as far down as the Haseko property, he said.

As for the Friends of Makakilo's concerns, "it's part of the process," Jones said. "You always expect someone to have either a differing view or have some issue." He said that Ho'opili regularly gathers input from its own task force of community leaders.

In a related matter, Horton averted a delay in the application process when it reached an agreement with the state Office of Planning, which makes recommendations on reclassification requests to the Land Use Commission.

Office of Planning Director Abbey Seth Mayer had called for Horton to provide a 10-year timetable for developing its project, which Horton did not do in its environmental impact statement as required by Land Use Commission rules.

Horton yesterday agreed to provide a timetable for its 20-year project by the end of the month.

Jones said a key reason Horton did not provide a timetable sooner is because of uncertainty about the development and routing for the city's rapid transit project, which will run through the project. Those questions were answered in recent months, he said.

While homes are projected to be built over a 20-year period, Jones said, most of the "backbone" infrastructure is expected to be built within the first 10 years.