比尔·多尔（Bill Doelle）每次阅读报纸的标题时吟着，说“考古学发现停顿建筑项目”。作为总部位于图森的沙漠考古学公司（Tucson Desert Archeology Inc.区域优化计划- 多埃尔（Doelle）和他的团队对当今的建筑工作人员的需求也与对过去的调查一样。

“The county has been developing for 25 years a pretty standardized procedure of assessing what’s in the ground and taking care of the big issues before construction gets underway,” Doelle says.

历史实际上是图森各地的脚下的脚下，因此，自1970年代以来，该县及其居民一直在保护和保存文化资源方面如此积极。迄今为止，已经发现了8,500多个考古和历史遗址，阐明了该地区不断居住12，000年的人类历史。Pima County Cultural Resources & Historic Preservation Office。

但这是在优化计划的expansion of the Ina Rd. Wastewater Treatment Facility that one of the most extraordinary discoveries was made. Dubbed Las Capas, the discovery is “the earliest, most complicated and sophisticated agricultural irrigation system discovered in North America so far,” says Loy Neff, program manager for the county’s historic preservation office. The extensive fields and irrigation trenches date back to the San Pedro Period, 1250 B.C. to 750 B.C.

The system was uncovered during archeological excavation begun in 2008, and was rated one of the 10 top discoveries of 2009 worldwide byArchaeology Magazine。随着建筑的进展，工作将继续持续到2013年。

Neff says the findings are significant to archeologists and historians because the ultimate question of how prehistoric populations developed and what technologies they used to produce food–along with the resulting changes in social organization—are critically important in understanding the whole prehistory of North America.

文化发掘

在计划的开始日期之前很久，考古学家就开始调查了一系列深度10英尺深的沟渠，使用标准的2英尺宽的backhoe桶，开始了调查。这些战es使考古学家能够在该地区的季节性洪水周期中查看数千年来铺设的各种土壤层，并选择区域以进行进一步调查。

Next, an excavation subcontractor stripped away the top layer of dirt, including up to 5 ft of fill placed during previous construction at the site.

沙漠考古学随后引进了自己的熟练反铲操作员，他们使用了专门的7英尺宽的刀片，称为“巨型抹子”。操作员一次可以每次驶下半厘米的污垢。Doelle说：“如果您与反铲一起工作足够长的时间，那么在地面上刮擦的金属刀片在告诉您的金属刀片上，您几乎会产生类似指尖的敏感性。”

It was during this time that the team noticed differences in the dirt coloration and pattern, indicating berms surrounding planting fields.

然后在某些区域进行手动挖掘，例如在住房坑中，工人在照顾田野或维护灌溉系统时可能会居住。

Desert Archeology项目总监Jim Vint说，总而言之，团队拆除了155,865立方米的污垢，并在几个地区进行了大量发掘，总计约7英亩，深度为9英尺。

发现了四个单独的灌溉系统，将一个灌溉系统像层蛋糕一样重建，被重大洪水事件所隔开，这些事件已覆盖了先前的系统，其冲积材料厚度为脚。这些田地估计占地80至100英亩，尽管随着越来越多的区域开放进行调查，这可能会发生变化。

主要农作物是玉米或玉米。令人难以置信的是，由于土壤颜色的略有变化，考古学家能够为田野内的每个玉米茎定位单个种植孔。

古老的灌溉系统以灾难性的洪水结束了其末端，该洪水密封了大量沉积物下的系统。Doelle说，这对公元前750年的农民来说是有害的，但对今天的考古学家来说是有益的，因为该地点的保存方式与庞贝伊在意大利的火山喷发中保存相似。

保持低调

为了最大程度地减少对施工时间表的影响，Neff从计划开始就参与了所有县公共工程项目，并密切努力就文化资源合规规则进行教育。新利18备用网址

“The earlier we get involved in their planning, the better we can assist them and the less chance we can cause them any delays,” Neff says. “My goal is to get in, get the info we need, do the archeology, meet the compliance requirements, and then get out, while not impacting the construction schedule. We’ve been able to do that out at Ina Road so far.”

Doelle说，考古学家完全融入了Ina Road的建筑团队，甚至从预先计划的早期开始就参加了每周会议。

Workers at the existing plant had no idea there was a virtual archeological goldmine underneath their feet. “I gave weekly tours for employees out at the plant, which opened their eyes as to what we were doing,” Vint says. “A lot of them were really surprised that they were working right on top of this 3,000 year old site. It changed their perspective on where they were working and the importance of history.”