翻刻
四月廿三日 松平伊賀守家来
片岡朔之助
私在所信州松代此程先御届申上候通大地震にて更級
郡山手村之内岩倉山抜崩犀川江押埋堰留候場所去
十三日夕一時ニ押切右川筋江押出し里方江ハ水口ゟ
左右之土堤押切乗越夫ゟ川中島一円二水押来城下
より一里程上同郡横田村辺より千曲川下続江一面ニ押
入候水勢甚強下筋ゟも追々湛来更二益水ニ相成専
致逆流居城際迄押入城外地陸よりも水高ニ相成候処
去ル文政年中御聞二達申上築候所水除土堤にて相凌
尤所々及大破候付種々手当急難相防候内減水致し候
故城内江ハ水入不申候得共城下町江ハ余程水入申候
右様之次第ニ付流末川辺村々も御領所中野村辺迄
致充満湖水之如ク相見候処追々及減水早速見分差
出候得共大小之橋々多分流失其上水引候而も地窪候処
水溜居或ハ道或者押掘等にて通路難相成場所有之
凡之見積も出来兼候得共犀川湛場破方之儀者段々水
嵩相増深サ弐丈余にも及ひ少々ツゝ水乗候ニ随ひ岩倉山
麓方追々欠崩麓之方ゟ多分欠込数十日湛水川中島江押
現代語訳
四月二十三日 松平伊賀守家来
片岡朔之助
私の在所である信州松代において、この程先にお届け申し上げました通り大地震により、更級郡山手村内の岩倉山が崩落し犀川に押し込んで堰き止めていた場所が、去る十三日夕方に一時に押し切れ、右の川筋に押し出し、里方へは水口から左右の土堤を押し切り乗り越え、そこから川中島一円に水が押し寄せました。城下より一里程上の同郡横田村辺りから千曲川下流続きへ一面に押し入った水勢は甚だ強く、下流筋からも追々水が溜まってきて更に増水となり、専ら逆流して居城際まで押し入り、城外の地面よりも水位が高くなりました。
去る文政年中にお聞き届けして申し上げ築いた所の水除け土堤によって凌ぎました。もっとも所々大破に及んだため種々手当てを急いだものの防ぎ難い内に減水したため、城内には水は入りませんでしたが、城下町にはかなりの水が入りました。右様の次第により、下流の川辺の村々もご領所中野村辺りまで充満し、湖水のように見えましたが、追々減水に及び早速見分に差し出しましたが、大小の橋々の多分が流失し、その上水が引いても地面が窪んだ所に水溜まりがあったり、道が押し掘られたりして通行困難な場所があり、概略の見積もりも出来かねます。しかし犀川の堰き止め場所の決壊については、段々水嵩が相増し深さ二丈余りにも及び、少しずつ水が乗るに随って岩倉山麓方が追々欠け崩れ、麓の方から多分に欠け込み、数十日湛えた水が川中島へ押し
英語訳
April 23rd Retainer of Matsudaira Iga-no-kami
Kataoka Sakunosuke
In my domain of Matsushiro in Shinano Province, as previously reported, due to the great earthquake, Mount Iwakura in Yamate Village of Sarashina District collapsed and blocked the Sai River, creating a dam. On the evening of the 13th, this blockage burst through all at once, rushing out into the river course. In the villages, it broke through and overflowed the embankments on both sides from the water intake, and from there water surged across the entire Kawanakajima area. The force of water that rushed across the area from around Yokota Village of the same district, about one ri upstream from the castle town, to the downstream continuation of the Chikuma River was extremely strong. Water also accumulated gradually from downstream areas, causing further flooding, creating a backflow that reached right up to the residential castle, with water levels rising higher than the ground outside the castle.
We managed to hold it back with the flood-prevention embankments that were built after reporting to and receiving approval during the Bunsei era. Although these were severely damaged in many places and we rushed various emergency measures, the water receded before we could effectively prevent it. While no water entered the castle itself, considerable water entered the castle town. Due to these circumstances, downstream riverside villages were also inundated up to the Nakano Village area of your domain, appearing like a lake. As the water gradually receded, we immediately dispatched inspectors, but most of the large and small bridges were washed away. Moreover, even after the water receded, there were pools of water in depressed areas and places where roads had been scoured out, making passage difficult. We cannot even make a rough estimate of the damage. However, regarding the breach of the dam on the Sai River, as the water level gradually increased to a depth of over two jō, and as water slowly rose, the foothills of Mount Iwakura gradually eroded and collapsed. Much of it was gouged out from the base, and the water that had been dammed for several tens of days rushed toward Kawanakajima—