W9128F21Q0059_Questions and Answers_Cultural Surveys_Version2.pdf

UPDATED ANSWER **Underlined information is the update** Can USACE clarify temporal affiliation of each site? Historic or prehistoric?

All sites except 24GF0373 and 39GR0015 are prehistoric sites.

NEW QUESTIONS AND ANSWERS

I suspect the acreages listed in RFP are unrealistic, in terms of cost (which would be enormous at the stated acreages) and also in terms of terrain fesibility and usefulness. I think they are probably derived from the corps' shapefiles or official site boundaries. From the information I currently have, they seem to be very general, and generally larger than the surveyable area or reasonable limits. In some cases boundaries seem to include parts of the lake or bluff sides.

An adjustment to the RFP has been made to provide more realistic and feasible survey acreage.

Is 100% coverage expected for geophysical? Approximately 100% coverage is expected, exceptions for areas unsuitable for testing due to safety or obstructions up to 10% of the area acreage are allowable where site size does not allow adjustment of survey area.

It calls for gradiometer survey plus additional coverage with other instruments. In most cases this will be appropriate, but gradiometer might be ineffective on some sites. It is probably most cost-effective to limit coverage with additional instruments to sampling or targeted survey of limited areas. Expectations for this are ambiguous in the RFP.

Gradiometer and soil resistivity are the preferred methods. Where gradiometer is inappropriate, soil resistivity and one additional method should be used.

Magnetic survey is much faster than the other methods, and the rate of coverage with each of these is different and can vary depending on appropriate sample densities.

Per Section 24 of the PWS, the contract will be awarded as a fixed price contract. As noted in the solicitation, this solicitation will be at the best value to the Government. The contractor must submit a quote consistent with the PWS and solicitation requirements.

Sample density and patterning is a core concern for good results and cost effectiveness, and should be specified in proposals and compared in evaluating them

Per Section 24 of the PWS, the contract will be awarded as a fixed price contract. As noted in the solicitation, this solicitation will be at the best value to the Government. The contractor must

Beyond area, terrain and vegetation are critical concerns in terms of rate of survey. The difference in rates of coverage can be an order of magnitude.

Per Section 24 of the PWS, the contract will be awarded as a fixed price contract. As noted in the solicitation, this solicitation will be at the best value to the Government. The contractor must

The site area (acres) in Tables 1-3 does not represent surveyable site area for geophysics.

Areas that may be feasibly surveyed are clearly

Tables 1-3 acreages for locations above 5 acres have been adjusted on Tables. Minimal (less than 10% of acreage) reduction of coverage may be much less in most cases. How will actual area of survey coverage be determined?

acceptable in cases where ground conditions prevent survey or would produce in meaningless results.

Magnetic gradiometer is expected to be the primary geophysical method.

With the secondary method (resistance or other), targeted survey or sampling of a more limited area is likely to be more feasible and cost effective. With additional methods, may coverage sample a lesser area than the primary method? If so, how will the amount of coverage be determined?

Adjustment of coverage would not be appropriate for conditions other than safety, feasibly, and data validity and within a 10% margin.

If magnetic gradiometer is not suited as the primary method, resistance, GPR and other alternative are generally much slower. Where a slower method is more appropriate as the primary, may adjustments be made to coverage or cost?

Per Section 24 of the PWS, the contract will be awarded as a fixed price contract. Adjustment of coverage would not be appropriate.

Where crops are present in agricultural fields, survey will cause crop damage. Are these areas to be avoided, or can survey be scheduled for when crops are not present?

Agricultural fields have been removed from the revised PWS. Only prairie hay is likely to be present. Contractor is encouraged to schedule surveys prior to heavy vegetation growth.

Where vegetation impedes or prevents survey, to what extent is clearing permitted?

Contractor may mow or string trim grass and small brush as necessary to accomplish the survey. Established trees will be left in place and may necessitate the reduction of survey areas in small sites or shifting of survey area on larger sites. Contractor is encouraged to schedule surveys prior to heavy vegetation growth.

It is often impossible to determine the state of vegetation without physically visiting the site. If clearing is necessary, may cost or area of coverage be adjusted?

Per Section 1 of the PWS, the contractor is responsible for all personnel, equipment, supplies, facilities, transportation, tools, materials, supervision, and other items to perform the activities. Section 24 of the PWS, the contract will be awarded as a fixed price contract.

Vegetation or other conditions may greatly reduce rate of survey, prevent survey entirely, or render it useless in terms of results. This may be impossible to determine without visiting the site.

In such cases, may cost or area of coverage be adjusted?

Per Section 24 of the PWS, the contract will be awarded as a fixed price contract. Minimal (less than 10% of acreage) reduction of coverage may be acceptable in cases where ground conditions prevent survey or would produce in meaningless results.

The solicitation says "the contractor may be permitted to perform small soil probes on a cultural resource site to determine the location of the ground based geophysical testing area." The utility of soil probes would be to examine soils to assess methods prior to survey, or to test anomaly sources after survey. Is this what was intended?

Yes, limited soil probes may be used to assess methodological validity prior to geophysical survey.